Imagine how difficult it is to provide any relevant information without you telling us what year, model, engine size or whether it's a petrol or diesel.
Let's guess it's a petrol engine for this exercise..
Non starting could be down to a fuel supply problem, a fault with the ignition system (where there is no spark at the spark plugs), a snapped timing belt, an immobiliser problem, no compression, an ECU or sensor issue, bad fuel injectors, blocked air filter or another wiring issue.

Rupert
June 2020