When you talk on the phone

[giddyman]

When you talk on the phone, you say "This is Mike," rather than "I'm Mike."

Can I say "It's Mike," instead of "This is Mike"?

How about "It's me, Mike"?

 

[NikkiBarber]

I am NOT an English teacher but it all depends on what phone you are answering and on the people who are calling you.
If you are answering your own phone when a friend is calling you, you can use any of the ideas you listed, except for "I am Mike." This would sound like you were introducing yourself to someone for the first time.
If you are answering a phone at work or in any situation where you need to be more formal and polite it would be better to either say your full name or to say "This is Mike (surname) speaking."

 

[NikkiBarber]

I am sorry, I read your question wrong. I thought you were asking for ways to answer the phone, but you could also be asking about how to introduce yourself when you are the one making the call.
If you are calling someone on the phone you normally say: "Hello, this is Mike Surname calling" or "Hello, my name is Mike Surname." Again, it will depend on the person you are calling.
Of course you will not need to give your full name when you are calling a close friend, but when it comes to professional relationships and strangers you should always be polite and introduce yourself clearly.

 

[giddyman]

Thank you, NikkiBarber.

The question was poor. Thank you for your helpful answers.

 

[lauralie2]

These are fine:

• This is Mike (speaking).
• It's Mike (speaking).
• It's me (speaking), Mike.
• Mike here.
• You've reached Mike.