Positive ions are pumped in and out of the axon, further up each time, to create a temporary attraction and draw the action potential along.
Information is conducted through the axon in the form of electricity, which is negatively charged. This is called the action potential.
The inside of the neuron is relatively negative compared to the outside. This is also called polar.
When the action potential enters the axon it stimulates ##Na^+## ions to enter, changing the normally negative cell interior to more positive. This obviously would attract the electrical action potential along the cell. Since the cell is becoming more positive, this is called depolarisation.
After ##Na^+## has entered and depolarised the cell, it causes potassium (##K^+##) channels to open and pump potassium out of the cell again, a process called repolarisation, and the cell turns back negative again.
Meanwhile, some ##Na^+## ions have spread out and opened voltage-dependent channels further up the axon, which pumps more positivity into the cell, attracting the action potential further along, repeating the process.
I think of it as a cartoon character chasing after a note tied to a thin string, being yanked across the pavement.