Hi Sarah.
Are you asking about creating a shared email mailbox that can be accessed by other team members from their own independent computers, Macs and Windows machines, on the same in-house network, or are you asking about creating a shared mailbox that can be accessed by multiple users of the same Mac when they are individually using that one Mac?
Mac Mail isn't really setup for creating a shared mailbox across multiple individual users on a corporate type business network, this is something that is created by the network administrator on the network server, or on one of the network computers using third-party software specially created for this purpose.
The other option, allowing multiple individual users of a single Mac to access a common shared email folder in Mac Mail also is not possible because on modern macOS's the email folder is encrypted, and whatever you store there is only visible to you.
For small businesses, that don't have an internal network, or network administrator, the usual route is to create a shared email group folder using a dedicated G-mail Collaborative Inbox. Each of your individual users have their own Google G-mail accounts, addresses and logins and are granted access to the single shared mailbox.
You redirect, automatically, or manually, incoming business emails from your personal Mac Mail address to that shared G-mail folder and all collaborative users will have access.
I think you will find that Outlook has the same possibilities, but can't recall if group shared mailboxes were free or only available with the paid-for Outlook business service.
A final possibility I can think of, if you only need the other users to view these messages then a possibility is to add an inexpensive NAS storage drive to your network, create a shared folder on that drive that all can access and print the emails you want to share using the save as PDF option then place this copy on the shared drive.
You would have to use a shared encryption key when setting up the NAS shared folder, to protect any documents placed there but this is fairly straightforward these days.
For simplicity probably a Google G-mail Collaborative Folder would be the best solution, with the added benefit that WFH users would be still be able to access that G-Mail shared folder remotely.
If the above is of no help you need to find a Small Business or Corporate Networking specialist to advise on the more common (paid-for) services that businesses normally implement for workgroup sharing.
HTH?
Will.