Preserved lemons are widely used in Moroccan cooking, and essential if your dishes are to taste authentic, but cannot unfortunately be replaced with ordinary lemons or limes.
Moroccan preserved lemons are pickled in brine and have a salty silky taste and texture which is difficult to describe. The peel loses its bitterness and adds a very distinctive flavour to a wide variety of dishes: in many dishes the skin only is used.
Preserved lemons are strangely addictive; stopping using them is more difficult than you think, once you have tried them in a variety of dishes.
In Morocco the thin skinned (doqq) lemon is widely used, along with the tart bergamot (boussera), but any lemon will be fine. Preserving your own lemons is not difficult, but it is time consuming.