How did Islam become Afghanistan religion?

Answer 1

The Islamic conquest of Afghanistan (642-870) began in the middle of the 7th century after the Islamic conquest of Persia was completed, when Arab Muslims defeated the Sassanid Empire at the battles of Walaja, al-Qādisiyyah and Nahavand. The Muslim Arabs then began to move towards the lands east of Persia and in 642 captured the city, Herat. By 667 AD the Afghan area was under invasion by the Arabs but in 683 Kabul revolted and completely routed the invading army which was led by the Governor of Seistan. It was not until 870 that Kabul and the Afghan area was brought under control by the Arabs. The complete conversion of Afghanistan to Islam was during the period of the Ghaznavids, in or about the 11th century.