Joneanne Nash
I'm not sure I understand your request. Do you want to:
1 -- Use an Outlook for Windows client and access your B.T. Broadband email account?
If so, either Classic Outlook or New Outlook for windows can do this if you add your BT account as an IMAP email account.
https://www.bt.com/help/email/manage-email-account/manual-settings/what-are-the-settings-for-outgoing-and-incoming-bt-email-servers
https://support.microsoft.com/en-us/office/add-an-email-account-to-outlook-for-windows-6e27792a-9267-4aa4-8bb6-c84ef146101b
2 -- Migrate your existing emails from BT to a new outlook.com email account, close your BT email account, and access your new outlook.com email account from Classic or New Outlook?
If so, you can do this. It will require exporting/forwarding your BT emails into the new outlook.com account. If this is the path you want to try, please advise and we can provide additional details.