How to register your manager as a vendor
From Protemos Wiki
you can try a workaround using "plus addressing" email scheme where emails with "+" sign after email account username are delivered to the same email address.
For example, you invited your manager with the following email:john@example.com So, you should invite them as your vendor using john+vendor@example.com
All the notifications will still be delivered to the main inbox - john@example.com.
Most email providers support such a workaround, but some of them do not.
Check with your email provider for the up-to-date information.
