By default, you're the owner of every document you create and of every file that you sync or upload. However, you can transfer ownership of Google documents and folders to anyone you'd like, as long as that person has an email address.
Note: You can't make someone outside of your domain the owner of your Google document.
After you transfer ownership, you'll have access to the doc as an editor.
Being the owner of a file gives you a lot of control over it, and once you change owners, you give up those controls. So before you transfer ownership, here are the things you’ll no longer be able to do:
When you transfer ownership of a folder from yourself to another person, the new owner of the folder becomes an editor of the files in that folder. The original owners of the files remain the owners.
Transfer ownership of your files, folders, and Google documents to another active account if your current account is being deleted. Once the account is deleted, you won’t be able to recover anything from your deleted Google Drive account.