How to specify the user's email in from when sending an email in php?

Question

PHP

Hello, now applications are coming from the site with the sender's address: "[email protected]" everything comes, but all the letters are in a heap. You need to make sure that the sender is the real address of the person, which he indicates in the appropriate field in the form. And when "[email protected]" becomes the sender's address, 90% of letters stop coming, and 10% fall into the "Spam" folder after a long period of time.
With similar I met on the majority of hostings. How to bypass it?

Answer 1

No way. SPF, DKIM and DMARK are not in vain invented.
Today you send mail from some user's address, tomorrow a spammer sends mail from your address.

Answer 2

Well, how did you want people to receive letters from mailboxes that do not belong to them and cannot belong to them?
If you receive a letter from the local prosecutor's office or a bank, and a million more possible options, will you like it?

Answer 3

You need to make sure that the sender is the real address of the person

and how will it help you organize if you receive a bunch of letters from different recipients?
if it’s quite simple, then as an option, the email can be added to the subject