Introduction
Open System Preferences and click Internet Accounts. Click your TechMail account, and then click the minus symbol (-).
Instructions
CAUTION: If you have made changes to items in Mail, Calendar, Contacts, Reminders or Notes while offline and those changes have not been synced to Microsoft 365, the changes will be lost when you remove the account from your Mac.
2) Click Internet Accounts.
3) On the left hand side, click on your TechMail account. Then, click the minus sign (-) in the bottom left.
4) Click OK to confirm.
OUTCOME
Your TechMail account items will be removed from the Mail, Calendar, Contacts, Reminders, and Notes apps on your Mac.