Use the SketchUp License Manager to search for your code using the email address and serial number associated with your original purchase.
Locating your is a common task for users maintaining "Classic" perpetual licenses in an era of subscription-based software. How to Retrieve Your 2016 License Details sketchup 2016 serial number and authorization code
A single-user license allows installation on up to two computers, but only one instance can be used at a time. How to Authorize SketchUp Pro 2016 Single user license 2016 SketchUp pro Use the SketchUp License Manager to search for