How can I create Email Template from a Salesforce Visualforce page?

Hi Ajay,
You can create Visualforce Email Template with custom controller.
reffer this link:
http://www.infallibletechie.com/2013/05/visualforce-email-template-with-custom.html

Hi Ajay,

• Enter Templates in the Quick Find box, then select Email Templates or My Templates—whichever one appears.
• Click New Template.
• Choose Visualforce and click Next.
• Choose a folder in which to store the template.
• To make the template available for use, select the Available For Use checkbox.
• Enter a name in Email Template Name.
• Enter a subject line for your template in Email Subject.
• In the Recipient Type drop-down list, select the type of recipient to receive email created from the template.
• Click Save.
• On the View Email Templates in Salesforce Classic page, click Edit Template.

Now you can build your own custom VF template through your coding and as per your requirements.

Hope this helps you.