You can greet someone saying Bonjour if you want to say hello or Good morning in French in formal way

Bonjour - Hello/Good Morning

The word Salut is more of a casual greeting. You can it when you meet someone again on a same day

Salut- Hi

You use formal Bonsoir when you meet someone first time in a day but during the evening time

Bonsoir - Good Evening/Hello

This is a casual salutation mostly used among close friends

Coucou - Hey

This salutation is exclusively used for telephonic conversations

Âllo – Hello

This is a formal way of saying goodbye in French

Au revoir! – Goodbye

This is the casual way of saying goodbye in French. It used mostly with close friends & family

Salut! – Bye

This is another casual greeting to tell someone you will see them later(unspecified time)

À plus! - Later!