You can modify a distribution list by adding or removing members, changing group settings, or updating permissions using Outlook, Exchange Online, or Microsoft 365.

Modifying Personal Contact Groups in Outlook

For Outlook on Windows or Mac, personal distribution lists are called Contact Groups (Windows) or Contact Lists (Mac):

1. Open Outlook and click the People icon to access your contacts.
2. Locate the distribution list/contact group you want to edit and double-click it.
3. To add members, click Add Members and choose from your Outlook contacts, address book, or enter a new email address manually.
4. To remove members, select the contact and click Remove or press Delete.
5. Save your changes by clicking Save & Close. Note: Changes to personal contact groups only affect your Outlook client and are not reflected in Outlook Web or organization-wide lists .

Modifying Organization-Wide Distribution Groups

For Exchange Online or Microsoft 365 distribution groups, you need appropriate permissions (group owner or admin):

1. Sign in to the Exchange Admin Center (EAC) or Microsoft 365 portal.
2. Navigate to Groups and select Groups I own or the specific distribution group you wish to edit.
3. To add members, click Members, then Add members, search for users, select them, and click Add.
4. To remove members, select the users and click Delete. Multiple users can be removed at once.
5. To configure delivery permissions, go to Settings > Delivery Management and specify who can send emails to the group.
6. You can also edit general information such as the group name, alias, description, and membership approval settings .

Additional Tips

• Dynamic distribution groups automatically update membership based on rules; editing individual members is not applicable.
• Mail-enabled security groups can also be modified similarly but may include access permissions to resources.
• Always verify that you have the necessary permissions before attempting to modify organization-wide groups. By following these steps, you can efficiently manage your distribution lists, ensuring that emails reach the correct recipients and that group settings align with your organization's communication policies.