Sync issues

Hi Apple Community

I have a frustrating issue related to syncing my emails on my mac with my ipad.

I used to be able to sync my yahoo accounts and all my folders by clicking in mail pressing on synchronizing yahoo but this does not work any longer! Also the sync icon is no longer on the top of the menu bar on my screen.

I have looked at various help and support info and tried giving new command as shown in help section in Terminal but no good!

Desperate as I need for all to be sync as I work from home and abroad so files need to have all emails replies etc in the correct places.

Anybody out there help me.

Thanks for reading this email.

Kind regards