though it might be good to point out that not building enough attraction and comfort would lead to compliance of her punching in a number on your phone but a number that aint necessarily hers

if a girl doesn't wanna give you her #, its probably because she doesn't want u calling her (she's not interested)
U gotta tighten up your game. Sure there's ways of getting her to give you her # but if you squeeezze it outta her, it's not a quality phone number. she probably won't call back. You're gonna have to spit additonal game ON THE PHONE! that means no body language, and u only have your voice and our words to attract her. It's not imposible, after all we're PUAs!

If she's interested then there's no problem, she might even give you the number if u don't ask for it! it's how confidently you ask for it, and how attracted or comfortable she is with you. Just like an opener "it's not what you say but how you say it"