Ok, so you’re right in that drugs are made in a liquid (generally a solvent, or water). Most drugs are solid tablets(although not all, we also make some drugs for injection).
To get the drug from a liquid to a solid we do a “crystallisation”.
You’ll probably know about dissolution, that’s basically the opposite. When you put salt in water, it will dissolve. If you put jelly cubes in cold water, then heat the water up, they will dissolve. Crystallisation is the opposite, we start off with the drug dissolved in a solvent, and we cool it down to make the drug crystallise.