Other Mailbox
Adding "Other" mailbox should be doable via desktop, the app is an inferior way to manage email, and it is infuriating being told to use the app while I am already using the desktop.
1st
ranked

Hi there! We'd like to assist you with this, can you message us directly on X at @YahooCare or on Facebook on our Yahoo Customer Care page? In case you do not have a social media account, please contact us at https://help.yahoo.com Thank you!