My tutorial about WordPress contact form 7 populate the value of a field dynamic.
Code to add to form:
[text your-name default:get placeholder "Your Name"]
URL to call post and add values inside form – just click and test!
Example mentioned in video:
Video: How to auto Populate Input Fields with URL Parameter
Source (in my eyes to complicated): https://contactform7.com/getting-default-values-from-the-context/
PS: CF7 Form was styled with free Contact Form 7 Styler plugin