Online games use random number generators (RNGs) to ensure their odds match the payout of land-based casinos. Mathematical analysis should indicate the payout will average over time.
If you're playing alone, sometimes you will be given the option to digitally spin the wheel yourself, but in some solo and all multiplayer online roulette games, you won't be in charge of when the wheel is spun. The wheel spin in online roulette is simulated by a Random Number Generator, or RNG.