Mention 4 the expressions of asking permission in formal situation
Could I..? May I..? Would it be possible for me to..? Would you mind if..?
Mention 3 the expressions of asking permission in informal situation!
Can I..? Do you mind if..? Is it okay if..?
Mention 5 expressions of giving permission!
Yes, please.., Sure, Go ahead, Absolutely sure, No problem, It is okay, Please, feel free..