how electron and proton have same value of charge
The elementary charge, usually denoted as e or sometimes q, is the electric charge carried by a single proton, or equivalently, the magnitude of the electric charge carried by a single electron, which has charge −e.
Here, electron and proton have the same value of charge means magnitude is same. And as we know that protons are positively charged and electrons are negatively so by default their charge/signs comes into calculation. So, we don’t say electron has negative value of charge and proton has positive value of charge.
Hence, we simply say value of charge on electron and proton is 1.6 x 10^-19 C.