Short answers, pulled from the story.
The Afghan mujahideen were Islamist militant groups that fought against the Soviet Union and the Soviet-backed Afghan government during the Soviet-Afghan War and the subsequent civil war. They were united by anti-communist and Islamist goals but divided across ethnic, ideological, and personal lines. The Western press widely called them "freedom fighters" and "Mountain Men."
The United States funded the mujahideen primarily through the CIA's Operation Cyclone, described as the CIA's largest and most successful covert operation ever. Pakistan's Inter-Services Intelligence controlled which factions received assistance, with the four fundamentalist factions receiving the largest share. Saudi Arabia, China, the United Kingdom, Egypt, and West Germany also provided support, alongside private donors and charities from the Arab states of the Persian Gulf.
The Peshawar Seven was a coalition of seven major mujahideen groups recognized by Pakistan and based in Peshawar. It comprised four Islamist factions, including Hizb-i Islami led by Gulbuddin Hekmatyar and Jamiat-i Islami led by Burhanuddin Rabbani, and three traditionalist factions. In 1985, under pressure from the king of Saudi Arabia, the seven groups formally united into the Islamic Unity of Afghan Mujahidin.
The portable Stinger surface-to-air missile was first used by mujahideen in September 1986. Some military analysts called it a "game changer" and coined the term "Stinger effect" to describe its impact on Soviet air operations, though a Russian general claimed the United States greatly exaggerated Soviet and Afghan aircraft losses, and the statistics largely came from mujahideen self-reporting.
After Soviet forces withdrew by the 15th of February 1989, the mujahideen continued fighting Mohammad Najibullah's government, which remained in power with Soviet aid until 1992. The factions captured Kabul on the 28th of April 1992, but the new government quickly fractured into a second civil war. This unrest allowed the Taliban to emerge, take most of the country, and establish the Islamic Emirate of Afghanistan in 1996.
Osama bin Laden was the most well-known Arab financier and militant among the international volunteers who came to Afghanistan to support the resistance against the Soviet occupation. These foreign fighters later became known as Afghan Arabs. Bin Laden went on to found al-Qaeda and mastermind the September 11 attacks on the United States.