Website Automation

Hey guys,
what to learn to automate the following process.
User puts link into a form, website orders automatically at a social media panel, likes for example.

I want to learn how to code something like that.
Would be nice if anyone knows some great course for that.

Greetings

You can create form with HTML + CSS

When the form was submited, you can get data from form with Ajax (Javascript), and send data to PHP file in backend to handle