Aqua regia or HCl/bleach do similar things, they both dissolve gold, you do not want base metals in the mix when you use either.
Aqua regia will dissolve thick pieces of gold metal easily, HCl bleach will have trouble with thicker metal, for this reason HCl/bleach is best used with foils or powders or fine gold.
The aqua regia can be hard to deal with especially for beginners, limiting nitric usage is very important for good results, the excess nitric acid will need to be eliminated before precipitating gold, if nitric is not consumed in the reaction this can be time consuming and difficult to do without having a boil-over, or getting the job done, can be a long and difficult process for the novice refiner.
HCl/bleach is easier to eliminate the chlorine to precipitate gold. Sometimes just letting it sit in the sun a few hours will do the job, other times just heating the solution is needed.
Note both of these work best the cleaner your gold is, the better you eliminate base metals like copper the better your results.
You need to remove copper and base metals before dissolving the gold, there are several processes depending on your material to do this like using nitric acid, or the other methods like by using the copper II chloride leach also called Acid Peroxide or AP method.
Keep reading, it is very confusing at first, but soon things will become more clear.