Let's think about the flow of water through a pipe to help us understand electricity. The flow of electrons in a wire is similar to water flowing through a pipe in your house that goes to your bathroom shower. If you turn on your shower and could look into the pipe at a given point, you would see a certain amount of water passing that point each second.
The amount of water depends on how much pressure or how hard the water is being pushed through the pipe. It also depends on the diameter of the pipe. The harder the pressure and the larger the diameter of the pipe, the more water passes each second.
The flow of electrons through a wire depends on the electrical pressure pushing the electrons and on the cross-sectional area of the wire.