Taps tend to be sold as being low pressure or high pressure. What does this mean? It simply means that the tap is suitable for either a low or high pressure water system. A low pressure system is typically around 0.2 bar and is gravity fed whereas a high pressure system is fed by the mains water pressure and is typically over 1.0 bar.
Determining whether you have a low water pressure system is relatively easy. If you have an airing cupboard with a hot water cylinder in it and a water tank in the loft feeding that cylinder then you probably have a low pressure system, otherwise known as a gravity system. If you are still not sure then turn on the taps in your bathroom. The cold water tap should have good pressure because most cold water pipes in the house come directly from the mains water feed. If the hot water tap has a significantly lower pressure when you turn the tap on then this indicates a low water pressure system.
If you find that you have a low pressure system then you need to buy low pressure taps. These taps do not restrict the flow rate in any way so you get whatever pressure your system is able to deliver.
Can a high pressure tap still work on a low pressure system? Yes, it can work but the flow rate is significantly reduced and could easily be rectified by fitting the correct tap in the first place.
Can a low pressure tap work in a high pressure system? As the internals are designed for maximum flow a low pressure tap in a high pressure system works exactly the same as a high pressure tap.