How To Change InfoPath Form to Browser-Enabled in SharePoint

After you make sure your Browser enabled Documents are set to Open as a Web Page under Advanced settings of your document library.
and


If your SharePoint is not configured right, you will see



First, you need to make sure your server has Form Service turned on



Then you need to make sure this feature is active on the site collection level.

Tips:

When your using an email link you need to make sure that the link uses the
full InfoPath URL or appends some query parameters.
If your URL looks like http://server/documentlib/myform.xml you would need
to append the openin parameter as follows:
http://server/documentlib/myform.xml?openin=browser
You can also use the full URL to InfoPath as follows:
http://server/_layouts/FormServer.aspx?XmlLocation=/documentlib/myform.xml?openin=browser
This will force InfoPath server to open the form in the brower.