Add or invite people outside your org to a chat in Microsoft Teams

Start a new group chat and add participants

1. On the left side of Teams, select Chat  and then New chat to start a new chat.

2. Type the email addresses, groups, or tag of the people you want to invite to chat. Each person may be from a different Teams org. 

3. Write a message in the text box at the bottom. You can also click the down arrow on the right to add a group name (optional) before adding your message.

Add participants to an existing group chat

Add external access participants to existing or ongoing chats that already include at least one external access participant.

1. Choose or be active in the existing group chat that you need to add the participants to.

2. Select View and add participants below your profile picture at the upper-right of Teams.  You'll see a small number next to it showing how many members are currently in the group. Then choose Add people .

3. Type the person's email address or tag. Then, choose if and how much of the chat history you want to include. Select Add. You’ll then see those people added to the group chat.

4. To start or continue the chat, type a message in the text box at the bottom and then select Send .

Access to chats

• External Access is turned on automatically, but an org's admin can turn it off or limit it. For example, they can block certain addresses or domains.

• Some outside orgs or external access capabilities may be blocked by your org, or your org may be blocked by them.​​​​​​​

Capabilities for external users​​​​​​​

• When a chat is created between a managed Teams org and a Teams Free use account, only certain options are available.

• A person's status indicator is always shown for people who use Teams and Skype for Business and only shown for people who use Teams Free after they accept a chat invite.

• External chat participants who use Teams and Teams Free may edit and delete sent messages, set delivery options, format text, use emoji, stickers, and GIFs in conversations, use @mentions, and show their status in a chat. However, they can’t share or attach files or use tabs or apps.

• In most cases, all chat participants can view each others profiles.

Compliance and external access

• An external label at the top of a chat indicates if there are any external participants in the chat. You'll also see an identifying label beside the names of any external participants in one-to-one and group chat participant lists. 

• An external chat remains external even if all external participants are no longer part of the chat.

• When you join an external group chat within an org, you're subject to the policies of that org. Also, the shortest retention policy applies. These settings decide how long a chat or message is kept.

• An external chat becomes read-only if all participants in the org where the chat was created are removed from that org.

• Data-loss prevention (DLP) and information barriers don't apply to External Access chats.

For more info about External Access and related settings, see Manage external access in Microsoft Teams or check with your admin.