Could/Would you get me an ice cream?

Hello Teachers,
Can the expressions ‘Could you …?’ and ‘Would you …?’ be used in both formal and informal English or are they interchangeable and neither formal nor informal.
I’ve read that yes, but then we have 'Can you …? and this one, is only informal, isn’t it?

Eg.
Could you get me an ice cream?
Would you get me an ice cream?

Thanks in advance.

Could, would and can c an all be used formally and informally.

Hello Beeesneees,
Thanks a lot. I really didn’t know that.

RtL