If you have an existing free account, you can choose to use the same email address to join a Business team. All of your docs will move with you to your Business team.
You can also choose to create a new account with a different email address. In that case, you’ll start with a brand-new, empty account.
If you delete a team or cancel your Business subscription:
Note for team admins: If you’re a team admin, all content you own will move back with you to your personal account, including shared docs that you’ve accessed before or have been invited to.
If you join or upgrade to a paid Business team from a free team:
If someone is removed from or leaves a team, any “private” content (docs they’ve created that haven’t been shared with anyone else) will migrate back with them to their personal account.
Any shared docs that were created by that member will move to the team admin’s account that removed the member.
Contact support for answers to any other questions you might have.