Set up a phone line / number in Japan: Things to know as a non-Japanese speaker ?

Hello everyone !

I'm living in Japan since a few weeks, and will be for atleast the next year.
For now, i've used an E-SIM without a Japanese phone number, but i would like to set up one.

Would you guys have any recommendations about which phone operator i should chose ?
And, last but not least, i would like any tips on which papers i should bring, which questions i should prepare too.
Since i'm learning Japanese but for now i'm a total beginner, i would feel a bit better if i could know a bit which kind of things / documents they may ask me 🙂 !

Thanks in advance, and have a great day !