What is the usual taxi fare from Kuopio Airport to the city centre? How can I book them without a Finnish mobile number?
At least Taksi1 seems to have fixed price list https://taksi1.fi/kuopio/taksin-hinta-kuopio/ (but not available now during covid) that should give you a hint of the price range
You can order beforehand by email email@example.com
The Kuopio airpost transpost page tells thare should be a public transport bus connection too