phone number

What's your phone number? (informal)

What's your phone number? (formal)

My phone number is 0735455577. 

email address

Can you give me your email address? (informal)

What's your email address? (formal)

My email address is hallo@dw.com.

to call

Can I call you? (informal)

Can I call you? (formal)

cell phone

cell phone number

I don't have a cell phone.

I don't have an email address. 

Are you on Facebook? 
(informal)

Are you on WhatsApp? (informal)