Auto-filling via URL parameters in Youform
The "auto fill via URL parameter" feature allows you to have Single Line input blocks and Rating blocks automatically filled out.
How it works:
Let's say you put "email" here:
Now you can add ?email=name@email.com to the end of your form's URL, and the email address " name@email.com " would be automatically added in the form.
Click this form link to see it in action 
You can do the same for auto-filling name, address, or almost anything else. Moreover, do the same with the URL in your embed code, if you are embedding the Youform in your website.
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For Rating blocks, you can do the same thing:
Then add ?rating=4 (or you could do 5) to the end of your form's URL: