Hi @ohammed Kasim ,
Welcome to our forum!
Therefore, I’m looking for a way to set up an address book or contact group that contains client emails and is accessible to my colleagues without the need for an Office 365 group or a distribution list.
I'm afraid that there's no such function in Outlook which meets your requirement. To make the contact list show in the “To” field for all users, we need to create the Microsoft 365 Groups or Distribution Groups. As i know:
- Microsoft 365 Groups are used for collaboration between users, both inside and outside your company. They include collaboration services such as SharePoint and Planner. Microsoft Teams uses Microsoft 365 Groups for membership.
- Distribution groups are used for sending email notifications to a group of people.
More information: Compare types of groups in Microsoft 365.
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