Réponse:
We start the letter with a title Madam or Sir or if we do not know Madam or Sir. If the recipient has a particular title, it is customary to mention it: Madam Mayor, Director General, Madam Deputy and you have to look at the Web ...
Explications:
Start with a greeting.
If you want to be funny or do things the old-fashioned way, you can write this “My dear… followed by the name of the comrade”. To be more casual, you can just write “Hello! Or put your friend's name followed by an exclamation mark (eg "Chris!").
