How to send emails from any address with postfix? [closed]

I’m very familiar with PHP, and I used to use the mail function. I really want to be able to use it on my Raspberry Pi 4 apache2 server. I have php installed, and the mail function always returns true. But it never makes it. It’s not any error with the code or my spam folder because I’m using the same script I used to and there haven’t been any updates to my provider. Anyway, I know I need to install postfix, but I don’t know how. PLEASE READ ON BEFORE GIVING SOME TUTORIAL LINK. Anyway, I need to set it up so that I can send email over the internet AND from any address. Thanks in advance!