Otherwise, to set up two-step verification, click the link to enable two-step verification for that account.
Now that you have two-step verification enabled, you need to create an app password to use instead of your general login credentials.
Open your old Gmail account again, find the confirmation email from Google, and copy the confirmation code—then switch back to your button in Gmail, and you can now choose to send emails from your old or your new Gmail address.
And when you return to new Gmail account's inbox, you’ll see all of the email messages from your old account are being imported into your new account—which could take quite some time if you have a lot of archived emails.
Let’s start with the bad news: there’s no fully automated way to merge two or more Google accounts into one.
If you have a G Suite at school or at work that’s going to be deleted and want to move the data to a different account first, need to use multiple accounts but hate switching between them, or if you just don’t want your email address to be anymore—there’s no quick and easy solution. You have to transfer data out of and into every individual Google product you use—Gmail, Google Calendar, Google Drive, and so on.
Now, you just need to work on updating your email address—jump ahead to the next section if so. If that didn't work for you, it's on to option 2 where you can forward emails from your old account to the new one.
2) Click the 3) If you have already enabled 2-Step Verification on your account, skip ahead to the steps below to create a unique App Password for your old Gmail account.Pick your poison, and follow the instructions below.