Use this function to specify if invoice comment is mandatory on the Project/Project Activity when reporting project time/cost/material against a Project Activity.
If the option Invoice Comment Mandatory is enabled when creating a Project the Project Activities when created inherit the setting. The setting on project level and activity level can be changed at any time.
Invoice Comment Mandatory need to be enabled on the Project/Project Activity.
Invoice comment is added to the Project Transaction for time/cost/material.