Answer 1

From my understanding, it allows a user to choose from options the web developer has set out.

Like me giving people a list of operating systems and ask them to choose which one(s) they use for computing.

Please read up on these in you need further clarification:
https://www.w3schools.com/tags/tag_datalist.asp
https://www.w3schools.com/html/html_form_elements.asp