How to replace comment URL field with PHONE Number of commenters

Good morning leaders,

I’ve been reading all over the web for more than four hours but all the tutorials does not address a NEWBIE what to put into the functions.php and where “specifically” to put it; beginning or at the end of the page.

My challenge is: my website is https://www.allianceinmotionnigeria.com/blog and I want to make sure that all comments that is submitted on the website collects these data:

1. Full Name
2. Email (not compulsory for commenting as against the default rules by WordPress)
3. Phone (HIGHLY REQUIRED for commenting)
4. Location
5. Comment

I’d be very glad if someone could just help me with the right code to input into the functions.php that will render these features.

NB: I have added a hook to unset ‘URL’ function before if you check the site. Kindly let me know if I should remove this entirely.

Please help me and I will be very grateful for your help in this community.