You can share your private TMs with other users by sending them the private key. In order to do this, click on the arrow of the dropdown menu next to the Import TMX button and select Share resource.
You need to enter the email address of the person you wish to share it with inside the text box.
If they have an account on Matecat, the private key will be added directly to their translation memory and terminology tab; otherwise, they will need to click on the Add a shared resource button and paste the key into the private TM key field and then click on confirm.
Please note that once a TM has been shared, this action cannot be undone. Only the job owner can modify the TM settings.
Can I remove a shared TM from a project?
If the project owner adds a shared TM to the job, the translator who shares that TM will see the TM key in his panel, but will not be able to modify the settings of that job.
This means that when the owner creates a project and sends it to the translator who shares the TM key, the translator cannot actually modify the settings of that TM. For instance, it's not possible to remove the update flag. Despite the fact that the flags on the panel can be modified, the change is not actually applied to the job.