Use @mentions to get someone's attention in Teams

microsoftteams mentions

Summary

To get someone's attention in a channel conversation or a chat, @mention them. Just type @ before their name and then select them from the menu that appears.

Note: You can also mention someone simply by typing their name. Start by capitalizing the first letter and as you continue to type the name, a list of people will show for you to choose from.

They receive a notification, which they can click to go directly into the point in the conversation where they were mentioned.

To get the attention of an entire team, try one of these:

Post something in the Team's general channel. The channel name appears bold for every team member.
Type @team to message everyone on that team.
Type @channel to notify everyone who has favorited that channel.

FYI: This is enabled by default unless a team owner turns this feature off

@mention with suggested people