How To Use These Phrases In Your English
Phrase 1 is the most common phrase that British people say. Note: we don't often say 'Bye-bye'. This sounds rather childish.
Phrase 2 is a little more formal.
Phrases 3, 4, 5 and 6 are quite informal and friendly. They mean that you expect you will see the other person again soon.
Phrase 7 is short and not very polite. You are saying that you are leaving without a farewell greeting.
Phrase 8 is a little old fashioned but quite informal.
Phrase 9 is also very informal and says that you expect to see the other person again soon.
We only say phrase 10 at night.