Ability to Add Custom Column In Manage Finanical Plan

Summary: Need an Ability to Add Custom Column In Manage Financial Plan 

Content (required): As per our business requirement, need to capture Activity Codes against each task in WBS structure of Manage Financial Plan page of a Project Task Structure.

I thought of Adding a Custom Column renaming the column as Activity Code, where it can be a Free Text or List of Values ,where i can Select the value from LOV or write the Activity Code as free text as per the Business Need.

Or

Let me Suggest an alternate solution ,if any.

Version (include the version you are using, if applicable):