Measuring power, current and voltage
"is this how we get billed for the electricity each month?"
No.  A meter keeps track of the actual energy (kiloWatthours) that all of your electric devices have used.  Typically, for a home, they calculate the kWh used * $/kWh to arrive at your energy cost.  Then they calculate taxes + surcharges + other fees &amp; add that to your bill.

They (the electric company) don't know what devices you have connected to your home wiring, so they don't have any means of computing the usage based on the electric facts that are provided on device labels.  Label data is consumer data, so you can determine how efficient one device is compared to another device, &amp; so you can estimate how much power &amp; cost the device may consume as you intend to use the device.