To archive or delete an email account, you must be the administrator of the account. Select 'Settings' from the top-right, and then 'Email Accounts'. This will take you to the 'Email Accounts' page where you can view your currently connected and archived email addresses.
To archive or delete, you must first restrict project access, which you can do by clicking the 'Settings' drop-down to the right of the email account, and selecting 'Security.'
Once you’ve removed all project access, click 'Okay'.
Return to the same 'Settings' drop-down, and select 'Delete / Archive'
You will be prompted with a pop-up asking you to type 'DELETE' to confirm this action. Do that and then click 'Okay'. Your email will now be listed under the Status column as 'Archived'. You may reactive this email at any time.