External users

Question

how to add external users as trustable contacts. regularly facing issue while sharing some important snips or document there is no option.

Answer 1

Add each external person as a guest member of a Team when they must appear in Teams and receive chats and files; Teams does not provide a separate “trusted contact” list for this purpose.

Add the external user as a guest

A team owner can do this in the Teams desktop client:

1. Open Teams and locate the relevant team.
2. Select More options (…) beside the team name.
3. Select Add member.
4. Enter the external person’s complete email address.
5. Select Add name as a guest, and then select Add.
6. Ask the person to accept the welcome email. They may then need to select their profile picture in Teams and switch to your organization.

Guests must be added to at least one Team before guest functionality becomes available. After accepting the invitation, they can participate in chats and channels and access files shared with them. Provisioning can take several hours—Microsoft documents that it may take up to 12 hours.^1^ ^2^

For channel collaboration, add the guest to the appropriate Team and share the file in that Team’s channel. Guests can access only resources specifically shared with them.^3^

Why the file option is missing in an external chat

Teams has two different external collaboration models:

• External access lets users find, call, meet, and chat with users in another organization. It does not give those users access to your teams, channels, sites, or files.^4^
• Guest access creates a Microsoft Entra B2B guest account and supports teams, channels, chats, and file collaboration.^5^

In a normal external-access chat, external participants cannot attach or share files directly. That is why the attachment option may not appear.^6^

If converting the person to a guest is not appropriate, upload the document to OneDrive, grant that person access using an externally shareable link, and paste the link into the Teams chat. This requires your organization’s OneDrive or SharePoint external-sharing policy to permit that recipient.^7^

If Add member or Add as guest is unavailable

Ask the Microsoft 365 or Teams administrator to check the tenant configuration:

1. Confirm that Teams guest access is enabled.
2. Confirm that Microsoft Entra External ID and Microsoft 365 Groups permit guest invitations.
3. Confirm that SharePoint and OneDrive external sharing permits the required sharing level.
4. Run the guest-access diagnostic in the Microsoft 365 admin center.

Guest access depends on settings across Teams, Microsoft Entra ID, Microsoft 365 Groups, and SharePoint.^1^

For external chat without guest membership, the administrator should use Teams admin center → Users → External access and verify that both the organization-level setting and the user’s external-access policy allow communication. If domains are restricted, the partner’s domain must be allowed, and the partner organization must also permit communication with your domain.^4^

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References

1. Guest access in Microsoft Teams
2. Add guests to a team in Microsoft Teams
3. IT Admins - Overview of external collaboration options in Microsoft 365
4. IT Admins - Manage external meetings and chat with people and organizations using Microsoft identities
5. Use guest access and external access to collaborate with people outside your organization
6. Add or invite people outside your org to a chat in Microsoft Teams | Microsoft Support
7. Is possible to share files through normal chats (no teams or groups; chats 1:1) between tenants? - Microsoft Q&A