Are there any shortcuts for the m command?

Yes, you can use ";message" as a shorthand.

What rank do I need to use the m command?

You need the Admin rank or higher in HD Admin to use this command.

Type ;m [Message] in the chat while playing a game with HD Admin installed.

No, this command only works in games that have the HD Admin plugin installed by the game developer.

HD Admin Admin

The m command sends the specified message to everyone on the game.

This command sends the specified message to everyone on the game.

;m [Message]

Example: ;m hello everyone!

This command sends the specified message to everyone on the game. Run this command from the in-game chat by typing ;m.