"How many amps go thru a power line from the pole to the house"

As many as you demand.

If you upgrade from a100 amp service to 200amp service do you have to change the line from drop to house???

Most likely but only your local utility can say for sure

The amperage of your service is capacity, not flow. Meaning a 200A service can flow 200A, but only "flows" what you are actually using.

The line from the pole to the house is NOT yours or your responsibility. The power company will change it at their discretion.

I don't know if it works the same everywhere, but I'll explain what happened when I upgraded to 200 amp service. Other cities may have a different process.

When I did a "heavy up" to get 200 amp service the electrician both pulled a permit and notified the power company he was changing the panel and meter base. When the electrician installed the 200 amp box he connected it to the new meter base with the proper size wire and then connected the new base to the old meter base (they were daisy-chained). The power company later came out and removed the old meter base and connected the power line directly to the new meter base. At that time they inspected the incoming line to determine if any changes were needed. In my case they just replaced the strain reliefs and did not change the power line itself.

Bruce