The difference
between current and voltage is often compared to water travelling through
a pipe.
The current measures how much water travels through the pipe. Sometimes
you have a big pipe and sometimes you have a little pipe, but neither matters
for the current - the current simply measures how much water goes through
it. Likewise, "current" means the number of electrons that travel through
a wire.
The voltage is a measure of how hard the water is being pushed through the
pipe. If you've got a huge pump driving water through a pipe, the water
is pushed through hard. If the pump isn't working well, it isn't.
Voltage is a measure of the potential difference between one place and another.