The control range depends on the frequency, power and how the transmitter sends the data (the 'mode'.)
More power gives longer range (much like a brighter light can be seen from further away.) However, as the frequencies are shared there are laws in each country1 which limit the maximum power you can use; this prevents it becoming a 'free for all' for who can push the most power out, which would cause interference issues for everyone. This is also more costly on battery life, so there is a trade off particularly on the airborne segment.
There are a selection of frequencies available for use on commercial drones - again, this varies slightly by country1. Common frequencies these days include 5.8 GHz and 2.4 GHZ, but 870 MHz, 35 MHz and others are widely available.
A higher frequency allows you to send more data in the same time span (this is why 5.8GHz WiFi is faster than 2.4 GHz WiFi) but drone control is not usually data rate limited - although, this is why FPV kit usually uses 5.8 GHz as you can get move video data through for higher quality and/or lower latency. Lower frequencies will travel further (for the same power), but also require larger antennas on the drone for optimum performance.
Digital communication is more resilient than analog, which will extend the range for all other variables being equal. There are also variations in the digital modes used; if a manufacturer builds greater redundancy into their signal the range will be better.
For much longer ranges, you can exploit larger infrastructure to carry your signal. Common technologies used for this are cellular (i.e. mobile phone) networks or satellite communications. This adds lag and can make manual control impractical, but can be combined with other technologies - for example, the satellite and cellular controlled drones I've flown only provide telemetry and autopilot waypoint adjustments over the satellite link due to several seconds of lag, but have a direct RF link for local/manual flight control.
 As an example, this page
contains information from the UK communications regulator on radio use for RC models.