Lost admin password
I want to set up a password for entering my MacBook Pro (Retina, 13-inch, Late 2013) but in order to do this, it is asking me to give another password (after clicking on a padlock symbol in 'system preferences/ users and groups') So is this the Admin password? Or? Ive tried the password I thought it might be and its not. So my question is how, do I reset this Admin (or whatever it is) password? Thanks for any advice!
MacBook Pro 13″, macOS 10.14