The term "Security policies" is a slight misnomer. It is also known under a more accurate term of Extensible Data Security (XDS). It is an evolution of record level security that was deprecated from AX 2012: you could still do this, but it wasn't a recommended approach.
In this scenario, we will create a policy that only allows access to vehicles of type truck. In this scenario, we have a team that only has access to trucks when creating service orders.