What is charge

2 answers

Read carefully.

https://www.google.com/search?q=charge+in+physics&oq=charge+in+physics&aqs=chrome..69i57.3747j0j7&sourceid=chrome&ie=UTF-8
There are a few fundamental characteristics of matter we have:
a. That matter is a form of energy.
b. That particles can have mass, charge, momentum, and have many characteristics of waves.
c. Charge seems to be based in the fundamental characteristics of one of the quarks, and quarks make up all of the observable particles that we observe to have rest mass.
Why do they exist? It is the nature of things we observe.