To transfer data from one Google Account to another, you cannot merge the accounts directly, but you can transfer data on a per-product basis. Here's a concise guide based on the information from the search results:

  1. Google Drive and Google Calendar:

    • Log in to the Google Admin Console (if you're a Google Workspace administrator) or your Google account.
    • Go to Apps > Google Workspace > Drive and Docs (or Calendar).
    • Click "Transfer Ownership" and fill out the emails of the donor and recipient accounts. Confirm your choice.
  2. Gmail and Contacts:

    • Log in to the Google Admin Console (if you're a Google Workspace administrator) or your Google account.
    • Go to Account > Data migration.
    • Select the migration source (Gmail or Google Workspace) and start the migration.
    • Choose the age of migrated data, migration start date, and options like migrate deleted mail and junk mail.
    • Click "Select Users," then add the donor's email and password (or reset the password if needed).
    • Start the migration.
  3. Manual Method for Non-Admin Users:

    • Log in to the donor's Google account.
    • Organize the data you want to transfer into one folder in Google Drive.
    • Log in to the receiving Google account.
    • Go to the donor's Google Drive and download the prepared folder.
    • Unzip the downloaded file and move the data to the receiving account.
  4. Other Services:

    • For services like YouTube history, you cannot directly transfer the data. You can, however, create an alias for your Gmail account to make it more usable.

Remember that this process is not a complete account merge, and some services may not have a direct transfer method. You may need to manually move data or use third-party tools like SpinOne for a more comprehensive solution.