The btw full form is By the way. A person often uses it to change the subject of a conversation. It can be used as a preface or a postamble to indicate a shift in focus.

B = By

T = The

W = Way

BTW, I like your watch (here, BTW is a prelude, meaning it comes before the content), and BTW, I like your watch (Here, BTW is a post amble, i.e., after the text). BTW is also sometimes used to refer to “getting back to work.” BTW’s most prevalent meaning on Snapchat, WhatsApp, Facebook, Twitter, and Instagram is “By the Way.”

It’s also become a common chat abbreviation for online communication like e-mail, online chat, and instant messaging. So, if someone wants to quickly change the topic of a conversation, he can use this Acronym in his chat, text messages, and so forth.