autofill the form of user info

Dear all,
i have a form here https://eco.ilearning.me/2013/10/17/testing/
and i want the form to be auto filled by user info
such as username, name and email
i have no idea how to do it even i found some articles
can anybody help me by telling step by step?

thanks

https://www.ads-software.com/plugins/contact-form-7-dynamic-text-extension/