Question

When two objects are rubbed together they get charged. Why?

Answer 1

When two objects are rubbed , there occurs the exchange of electrons which creates a disturbance on the net charge on any body.
Thus, the body gaining electrons might become negatively charged body and the body giving more electrons out rather than getting from the other body and ultimately loosing more electrons becomes positively charged body.

Answer 2

When two objects are rubber together they get charged

Electrons move

One object gets positively charge and the second object gets negatively charge