Meta, the parent company of Facebook, is introducing Slack-like shortcuts to Messenger that let you do things like send a message silently or quickly call up a GIF while you’re chatting with your friends.
Two of the shortcuts are available today, March 29th, according to Meta: @everyone and /silent. @everyone will let you notify everyone in a chat, which could be useful if you want to make sure to get everyone’s attention. (On behalf of your friends’ notifications, I beg you to please use this one responsibly.) However, if you want to send a message without pinging the whole group, you’ll be able to use the /silent shortcut, Meta says.
In “the coming weeks,” there will be a few more shortcuts. /pay will let you send or request money right from the Messenger chatbox and will be available soon on iOS and Android in the US. Type /gif and a topic of something you want a GIF of to see some potential options to drop in the chat. This feature will be available soon on iOS. And /shrug and /tableflip, which will also be available soon on iOS, will let you drop the classic ¯_(ツ)_/¯ and (╯°□°)╯︵ ┻━┻ emoticons without having to type them out yourself.
Source: https://www.theverge.com/2022/3/29/23001776/messenger-shortcuts-commands-silent-replies-everyone-pay-gif-shrug-table