Step 1:
Please get Foxit Reader button from https://www.foxitsoftware.com/img/icon_getreader.gif and upload it to your website server.

Step 2:
Add the below code to your website's homepage:
<a href="http://www.foxitsoftware.com/pdf/rd_intro.php">
<img border="0" src="icon_getreader.gif" width="88" height="31"></a>

Note: The src above is the path where you input to save the icon_getreader.gif picture.