If a friend ask you how to transfer documents from one Google Drive account to another, you should let him/her clear another what? Another Google Drive or another cloud drive? Generally speaking, it is another cloud drive. Because we can share files between Google Drive, it is not a problem.
How to move document from Google Drive to another cloud? Download then re-upload? No! You can directly do it with MultCloud. MultCloud is a platform to manage cloud services and sync, transfer across cloud services. Tutorial please visit: https://www.multcloud.com/tutorials/transfer-google-drive-to-another-account.html.
If you try Chrome or Vivaldi, we recommend you add extension of MultCloud, read to learn: https://chrome.google.com/webstore/detail/transfer-to-google-drived/dhkemmehlndncfkilljmpeacciajkfag.