Could you tell me how to begin and end in an E-mail writing?
I don't know the words if corrected when I wrote an e-mail.
If I write to a stranger, can I use: Dear Sir/Madam
If I know this person: Dear Mr/Ms surname
My friend: Dear first name
End: Kind regards / Best wishes / All the best
I'm not sure for this kind of words, please help me.
What different between formal and informal e-mail writing of beginning and end?

