Meaning of !! In text messages reply

Ask the person that sent it to you. It could mean different things to different people depending on what they were responding to. If you have a technical issue with your phone, feel free to post that question on these forums.

You're welcome. It is just a way to really emphasize a statement. I could say "I'm so angry!!" and I could say, "I'm so excited!!" and I am simply emphasizing my sentiment.

Bonjour! or since it's evening, should it be Bonsoir?

The exclamation mark (!) (also known as exclamation point in American English) is a punctuation mark usually used after an interjection or exclamation to indicate strong feelings or to show emphasis. The exclamation mark often marks the end of a sentence, for example: "Watch out!"