2469402 - Email Signature in Email Notification Templates

Customer wants to customize the email signature for each form.

SAP SuccessFactors HXM Suite

The Email Signature is not designed to be form specific. You can only create a custom signature for each language you have enabled. 
It is not possible to have a different signature for each form you have configured in the system.
This is why the drop down menu to choose a different form is frozen when you access 'Email Signature' : 

Email Signature, Email Notification Templates,Email Behavior , KBA , LOD-SF-PLT-NOT , Email Notifications , Problem