Extended warranties are like an insurance policy you can buy for a vehicle to cover it generally for mechanical failure or breakdown.
An extended warranty is bought separately by you and is not a substitute for any statutory warranty that may apply.
You should carefully weigh up the value of extended warranties and, in particular, check to see they are not simply doubling up on the implied warranty they already have under law.
Most extended warranties have extensive lists of exclusions and are often conditional on you having your vehicle serviced by the selling dealer.
An extended warranty requires you to do certain things for it to remain valid, such as regular servicing.
Check what servicing requirements apply, eg what products you must use, how often and at what cost, and where.
Check what is and isn't covered by the warranty.
Failure due to fair wear and tear may not be covered, so think about whether it is worth it to you.
Shop around and satisfy yourself that the warranty is value for money. The costs vary considerably.