How to Tell Who Added a User to a Particular Group

@akaprobham Afaik, until and unless you setup an application (such as "User and Group Management Application 16.1+" at http://bit.ly/2ahz2AP) that captures the data from a place(From Process in form of Action/Related Action but not from the 'People' tab in Designer) where you can capture the data and make updates in DB, you may not be able to obtain the data you want. In short it's not available OOTB and the application mentioned above should help you and you may try customising it to meet your requirements.

@akaprobham Afaik, until and unless you setup an application (such as "User and Group Management Application 16.1+" at http://bit.ly/2ahz2AP) that captures the data from a place(From Process in form of Action/Related Action but not from the 'People' tab in Designer) where you can capture the data and make updates in DB, you may not be able to obtain the data you want. In short it's not available OOTB and the application mentioned above should help you and you may try customising it to meet your requirements.