How do I add a new mailbox to outlook?

My outlook doesn't have the File tab. Only Home, View, and Help.

I haven't found anywhere that you can add an account.

Dear Lois Tucker1

Welcome to Microsoft Community.

I understand that you are having trouble adding a new mailbox to Outlook.

According to the thread you posted, are you using classic Outlook? You can refer to the steps below to add a mailbox in classic Outlook:

1. Select File > Add Account.
2. Enter your email address and click Connect.
   
3. If prompted, enter your password again, then select OK > Finish to start using your email account in classic Outlook for Windows.

If your page is different from the one above, you may be using the new Outlook. You can refer to the steps below to add a mailbox in the new Outlook:

1. On the View tab, select View settings.
2. Select Accounts > Email accounts. You can now add a new account.
3. Under Email accounts, select  Add Account, and select a suggested account from the dropdown menu or enter a different email address. Click Continue. **Note:**Some non-Microsoft email providers, like Gmail, Yahoo, and iCloud, require you to change some settings on their websites before you can add these accounts to Outlook.
4. If prompted, enter your password for the account and select Done.

I hope the above information is helpful to you. If you have any progress on the issue, please feel free to let me know.

Kind Regards,

Hardyjoe.J|Microsoft Community Support Specialist

Every time I try to add a new email account following the first set of instructions, old email addresses are auto-populated from a previous employer and I am unable to enter new email addresses.