Expansion started in Northwestern India/Central Asia in the 7th century, with skirmishes between forces of the Kalif Umar and various Indian kingdoms and fiefdoms in modern-day Pakistan. These ended in mid-750 CE with the defeat of the Arabs and return west.

These resumed in the 11th century with Mahmud of Ghazni pushing into Peshwar, Pakistan. During this time Buddhist and Hindu temples were looted and people were forcibly converted to Islam. Islam historically had tolerance for Judaism and Christianity, "People of the Book" but not Hinduism and Buddhism which it saw as idolatrous due to rather common use of icons and elaborate statues/temples ( Buddhas of Bamiyan, in Afghanistan ).

Next, Mu'izz al-Din, from Ghor, Afghanistan, in 1173 he began a campaign pushed into Punjab but was defeated in 1191. The following year he attempted again and succeeded, with his eyes on taking Delhi. He succeeded in establishing the Delhi Sultanate. He was killed in 1206, and the Mamluk Dynasty took the reins, from here Muhammad bin Bakhtiyar Khilji began attacking as far as modern-day Bangladesh, destroying Nalanda, a Buddhist university, burning and desecrating the temples and destroying years of documents. This was the fate of many other Hindu and Buddhist universities, which had coexisted for over a thousand years.

The Delhi Sultanate passed through a few dynasties, Mamluk, Khalji, Tughlaq, Sayyid, Lodhi to name the major important ones. The sultanate remained relatively stable, surving raids from the Mongol Empire, but losing Pakistan and Afghanistan to the Mongols. Tughlaq was the greatest extent, nearly reaching the tip of India, but it declined heavily after the Timurids sacked Delhi in 1398, before Timur Lang took it over finally in 1526, forming the Mughal Empire, which lasted until Britain took India from them.

Sources

The War of the Three Gods: Romans, Persians and the Rise of Islam

Medieval India: From Sultanat to the Mughals (1206-1526)

Tīmūr Lang, Encyclopaedia of Islam