Unless you hold a current CAA permission or exemption for drone operations or have an appropriate achievement certificate or award (such as the BMFA ‘A’ certificate) from a CAA reviewed ‘competency scheme’ if you are flying a drone or unmanned aircraft (including model aircraft) weighing between 250g and 20kg you will need to take and pass an online education package. This is free and renewable every three years.
You can take the training at Register-drones.caa.co.uk
If you want to become an approved commercial drone operator then you should contact an approved assessment organisation to help you develop an operations manual and check you meet the necessary requirements. You can find out more about that, including a list of assessment organisations approved by the CAA, on the CAA’s website .
There are also many local and online training courses available for drone safety including NATS’ online course at www.nats.aero/apps/hobbyist/