How to use <apex:column>  in Visualforce Page?

<apex:column>:
A single column in a table. An < apex:column > component must always be a child of an < apex:dataTable > or < apex:pageBlockTable > component.

This tag supports following attributes:

Attribute	Description
breakBefore	A Boolean value that specifies whether the column should begin a new row in the table. If set to true, the column begins a new row. If not specified, this value defaults to false.
colspan	The number of columns that this column spans in the table. Note that this value does not apply to the header and footer cells.
dir	The direction in which text in the generated column should be read. Possible values include "RTL" (right to left) or "LTR" (left to right). Note that this value does not apply to the header and footer cells.
footerClass	The style class used to display the column footer, if defined. This attribute is used primarily to designate which CSS styles are applied when using an external CSS stylesheet.
footercolspan	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footerdir	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footerlang	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footeronclick	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footerondblclick	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footeronkeydown	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footeronkeypress	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footeronkeyup	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footeronmousedown	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footeronmousemove	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footeronmouseout	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footeronmouseover	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footeronmouseup	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footerstyle	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footertitle	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
footerValue	The text that should be displayed in the column footer. If you specify a value for this attribute, you cannot use the column's footer facet.
headerClass	The style class used to display the table header, if defined. This attribute is used primarily to designate which CSS styles are applied when using an external CSS stylesheet.
headercolspan	The number of columns that the header column spans in the table, if defined. This attribute cannot be used in Visualforce page versions 16.0 and above.
headerdir	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headerlang	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headeronclick	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headerondblclick	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headeronkeydown	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headeronkeypress	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headeronkeyup	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headeronmousedown	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headeronmousemove	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headeronmouseout	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headeronmouseover	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headeronmouseup	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headerstyle	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headertitle	This attribute was deprecated in Salesforce API version 16.0 and has no effect on the page.
headerValue	The text that should be displayed in the column header. If you specify a value for this attribute, you cannot use the column's header facet. Note also that specifying a value for this attribute overrides the default header label that appears if you use an inputField or outputField in the column body.
id	An identifier that allows the column component to be referenced by other components in the page.
lang	The base language for the generated HTML output, for example, "en" or "en-US".
onclick	The JavaScript invoked if the onclick event occurs in the column --that is, if the column is clicked. Note that this value does not apply to the header and footer cells.
ondblclick	The JavaScript invoked if the ondblclick event occurs in the column that is, if the column is clicked twice. Note that this value does not apply to the header and footer cells.
onkeydown	The JavaScript invoked if the onkeydown event occurs in the column  that is, if the user presses a keyboard key. Note that this value does not apply to the header and footer cells.
onkeypress	The JavaScript invoked if the onkeypress event occurs in the column that is, if the user presses or holds down a keyboard key. Note that this value does not apply to the header and footer cells.
onkeyup	The JavaScript invoked if the onkeyup event occurs in the column that is, if the user releases a keyboard key. Note that this value does not apply to the header and footer cells.
onmousedown	The JavaScript invoked if the onmousedown event occurs in the column that is, if the user clicks a mouse button. Note that this value does not apply to the header and footer cells.
onmousemove	The JavaScript invoked if the onmousemove event occurs in the column that is, if the user moves the mouse pointer. Note that this value does not apply to the header and footer cells.
onmouseout	The JavaScript invoked if the onmouseout event occurs in the column that is, if the user moves the mouse pointer away from the column. Note that this value does not apply to the header and footer cells.
onmouseover	The JavaScript invoked if the onmouseover event occurs in the column that is, if the user moves the mouse pointer over the column. Note that this value does not apply to the header and footer cells.
onmouseup	The JavaScript invoked if the onmouseup event occurs in the column that is, if the user releases the mouse button. Note that this value does not apply to the header and footer cells.
rendered	A Boolean value that specifies whether the component is rendered on the page. If not specified, this value defaults to true.
rowspan	The number of rows that each cell of this column takes up in the table.
style	The style used to display the column, used primarily for adding inline CSS styles. Note that this value does not apply to the header and footer cells.
styleClass	The style class used to display the column, used primarily to designate which CSS styles are applied when using an external CSS stylesheet. Note that this value does not apply to the header and footer cells.
title	The text to display as a tooltip when the user's mouse pointer hovers over this component.
value	The text that should be displayed in every cell of the column, other than its header and footer cells. If you specify a value for this attribute, you cannot add any content between the column's opening and closing tags.
width	The width of the column in pixels (px) or percentage (%). If not specified, this value defaults to 100 pixels.

Visualforce Example:

<apex:page standardController="Lead" recordSetVar="Leads">

  <apex:pageBlock title="Columns">

         <apex:pageBlockTable value="{!Leads}" var="le">

             <apex:column value="{!le.name}"/> 

             <apex:column value="{!le.Phone}"/>

             <apex:column value="{!le.Company}"/>

             <apex:column value="{!le.Status}"/>

             <apex:column value="{!le.Email}"/>

         </apex:pageBlockTable> 

     </apex:pageBlock> 

</apex:page>