Sulfuric acid itself finds no use in pyrotechnics, but it can be used in the preparation of an number of useful compounds for which reason it is included here. Sulfuric acid can also be used to ignite chlorates or chlorate containing mixtures, although in practical pyrotechnics this is not actually useful.
Sulfuric acid has many sources. It can be bought at many laboratory supply stores and web sites. The major drawback to ordering on the web is that there will be a hazmat fee for larger quantities and higher concentrations. An alternative is ordering Sodium bisulfate which is some what cheap and doesn't require hazmat shipping. Then using it in solution where it will have a pH of 1.4 in a 1 molar solution and will behave like Sulfuric acid. Other sources are liquid lead acid battery's, humidifier cleaner, and drain opener. Sulfuric acid can also be made at home but it will be in an unusable low concentration and small amount and not needed to be explained here.
Sulfuric acid and its fumes are extremely corrosive. Wear proper protective clothing (gloves, apron and a face shield are minimal) and provide adequate ventilation when working with it. Reactions with metals often produce flammable hydrogen gas (hydrogen). The presence of acid can cause spontaneous reactions in many pyrotechnic mixtures and should at all times be avoided. When working with sulfuric acid, have no chemicals or compositions nearby to prevent contamination. Make sure all traces of acid in chemicals produced with sulfuric acid are removed if they are to be used in pyrotechnics compositions.