Which one is the frame number? I have two numbers under my frame, can you help me understand which one is the frame number? Is it the same thing as serial number? And what is the other one? The make of the bike is Leader Fox, the two serial numbers I can read are
DA2019292 and M1301617 (or MI301617 )

I want to register the bike on the website that helps in case it's stolen. Also, police would need this number too. So I only need some number that is unique within this bike model.
You will need to contact Leader Fox to answer this question.
The Leader Fox website does not have any information on which of those numbers is the bicycle serial number.
Here is a link to the manuals for their bikes.
Their manuals do contain information on the serial number for the motors on their e-bike which is not the same thing as the serial number for the whole bike.
Here is a link to their contact page