Three fields, checked separately because they fail for different reasons. Between them they decide which searches you are a candidate for and whether anything can confirm that your listing and your website are the same business.
Category decides what you are considered for
This is the first thing Google uses to decide whether you are a candidate for a search at all. Choose the most specific one that describes what you actually do. "Car detailing service" beats "Car wash". "Emergency plumber" beats "Plumber", if that is your trade.
Add secondary categories for your other services, and keep the primary one the thing you most want to be found for. It carries far more weight than the rest. If you never set one, Google guesses from what it can see, and a guess is often close but wrong in a way that puts you in the wrong searches.
The phone number has to match your site
We compare the number on your listing with the one on your website. When the same business gives two different numbers, anything trying to confirm who you are has to pick one, and the safest thing for it to do is trust you slightly less.
Whichever number is current, change the other so they match exactly. If you use a call-tracking number anywhere, put your real one on the Google listing. And check any directory entries while you are there, because the value comes from every copy agreeing.
Address, or the towns you cover
If customers come to you, set the full address and make sure it matches your website. If you travel to them, switch to a service area and list the towns you actually cover rather than a radius that flatters you. An AI asked for somebody in a town you list will name you, and a wasted call helps nobody.