How can I get current user when a value is changed?

I have a form which have several choice fields (YES/NO/NA) and I’d like to capture current user and time/date when each field is changed.  Each field will be edited by different user from different offices, and I set a rule to make each field active for right group of people.  Can someone teach me what is the most easy/simple way to do this?  It’s on SharePoint 2016 On-Prem, and I use Classic Form.