Currently, you can only transfer prototypes. Transferring ownership of other project types isn't possible.
Comments will transfer with prototypes.
To transfer ownership of a prototype:
Sign in to your account and navigate to the Projects page.
Click to open your desired prototype.
At the top of the prototype dashboard, next to Assets, click the ••• (more) icon.
Click Transfer Ownership.
To transfer to an existing company or team, click the drop-down menu. Alternatively, click the link Or transfer this prototype to another user via email and enter the account owner's email address.
Click Yes, Transfer Prototype.
InVision will then send the recipient an email invite. After accepting the invite, the recipient becomes the prototype owner. If the prototype causes the recipient to exceed their project limit, they will need to upgrade their plan.