Form
Can / Shall / May + I + Verb?
Can I get you a coffee?
Shall I help you with your bags?
(Formal) May I take your coat?
Meanings
Offering to Help
We use these modals to offer to do something for someone else.
Can I…? – Informal and friendly.
Can I give you a hand with that?
Shall I…? – Polite. Asks for the other person’s opinion on your offer.
It’s getting dark. Shall I turn on the light?
May I…? – Very formal. Often used in customer service settings.
(A waiter to a customer) May I take your order now?