How to include additional action like "Add Assignment" under Action drop down in Person Management

Summary:

We need to include additional action like "Add Assignment" under Action drop down in Person Management. We have already checked through Sandbox structure under Person Management Tab level but such task is not exists to enable. Is there any way to enable the action like "Add Assignment" link under Action drop down.

Content (required):

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

Code Snippet (add any code snippets that support your topic, if applicable):