A free spin is essentially an offer that a casino gives to its players to spin the reels free of charge and have the opportunity to win real cash. The free spins may be given to both new and current customers, and it's one way to reward and encourage them to continue betting.
The modern Islamic Republic of Iran is the direct successor of Persia, one of the most long-standing empires in history, having lasted for millennia. Unsurprisingly, the government has banned all forms of gambling due to the religious ban on games of chance. The ban is rigidly enforced, and international mobile online gambling casinos are blocked.