Hope you all are staying heralthy in these times 🙂
Since the Quarantine I started learning WordPress, Html, CSS and PHP.
I see it will take some time but it is a lot of fun.
So I stumbled on a Problem recently:
I have an Registration Form on my Website wich gives the role “Subscriber” by default to everybody who tries to register, but I want a specific E-Mail Domain to get a different role.
I found a Post about this but I dont know where I should insert the PHP Code?
fuktions.php in my Themes folder? I would be really thankfull if someone with more knowledge could help me.

Thank you and have a great day.

P.S.
Im using WordPress 5.4.2 with Woocommerce and the Theme Shop-Isle