Email Templates and Insert Signature button to be setup for Custom entity

Dear Team,

I am new to Dynamics. Currently we are doing Adobe E-sign integration with Dynamics 365. As part of the requirement, there is a request to populate Email templates button and Signature button in Agreement entity which was created as part of Adobe E-sign Integration.

I tried this using Ribbon workbench with no luck. Is there a way to add 'Insert Email templates' and 'Insert Signature' button showing in custom entity, in my case its agreement entity.

Your help and guidance on this is much appreciated.

Thanks

Gowtham