The earliest mention of gunpowder in india comes from the mid-late 13th century, most likely introduced via the Mongol Empire. Early on the most popular military applications were rockets, fire arrows and firebombs, although eventually various sizes of cannons and mortars started to be used for both destroying and defending fortifications.

Matchlock firearms were potentially first introduced via the Ottomans in the late 15th century. When Portuguese explorers arrived in the early 1500s they noted that coastal cities were typically well-supplied with artillery and gunners. However they considered their own cannon and muskets more effective than those used by the Indians. Matchlock muskets are first mentioned being used in significant numbers in warfare during the conquests of Babur in the 1520s, with musketeers typically firing from the top of elephants or behind a mobile barricade of wagons which had been chained together.

Matchlock muskets in India didn't replace traditional weapons to the same extent that they did in europe, however musketeers tended to be relatively well-paid and respected, especially among the Mughals. Muskets would also occasionally play a major role in peasant rebellions when they could acquire them. During the second half of the 17th century matchlock muskets also started to become a popular cavalry weapon. For the Mughals small, elite corps of mounted musketeers proved extremely effective at suppressing rebels and deterring enemy raids. As a result, other groups such as the Sikhs started to follow suit.

Source: Gunpowder and Firearms: Warfare in Medieval India by Iqtidar Alam Khan