Hi my name is***** a car technician and I’ll help with your question.
This is the MIL or Malfunction indicator lamp. It will come on when a fault code is recorded in the engine control unit. If there are no problems with the car it may be a simple sensor fault. Firstly, if your comfortable doing so, disconnect the negative terminal of the battery for about 30 seconds, reconnect and see if the light is still on as this will reset the light if it's a one off glitch. If it's still on, the car needs to be plugged into a diagnostic scanner which will give a fault code and description of the exact cause, often it can simply be cleared with the diagnostic scanner. Otherwise it need repairing as per fault code.
Providing the car is running as normal, there should be no problems using the car as normal in the short term with this light on. However depending on the problem you may suffer from reduced economy and higher emissions so it's best to get it checked ASAP
Please feel free to reply if you need further assistance with this. Thanks, Ross.