Generally speaking a "law" is "primary legislation", meaning it has been debated and passed by a parliament of some kind, while a "regulation" is "secondary legislation", meaning that it has been created by a government department acting under the authority of primary legislation.
For instance, suppose the parliament in a country creates a general law about road safety. Part of that law will require the transport department to write regulations about the construction of motor vehicles. These regulations are "law" in the sense that you are obliged to follow them, but they are actually written by civil servants in the transport department. This way the parliament doesn't have to have a debate and pass legislation every time someone invents a new kind of seatbelt or windscreen wiper.
From the point of view of citizens trying to obey the law the distinction doesn't matter. Hence the term "laws and regulations" is used to cover both. However you could just say "laws" because the law requires you to follow the regulations anyway.