Here is some general informations about the Iran visa (e-visa) and how to get it :
Visitors to Iran must obtain an Iran Visa from one of the Iranian diplomatic missions unless they come from one of the visa exempt countries or countries eligible for Iran Visa on arrival.
All visitors must hold a passport valid for at least 6 months.
Iran Tourist visa is getting easier and easier and Iran is making a lot of progress, hoping to host 20 million visitors in 2025 with easy Iran Visa procedures. Iran Visa on arrival is possible for many citizens, for a duration of 30 days, while more countries are getting the visa-free treatment.
Now these are the ways to obtain e-visa to enter Iran :
-Iran Visa On Arrival at the airport (30 days duration, costs depend of your nationality)
-Iran 30 days Visa which can be obtain prior to your arrival in any Iranian embassy/consulate.
It is also possible to extend your Iran Visa, no matter if you get it at the airport or prior to your arrival. The process is relatively simple, even though the possibility of getting your demand of extension deny still exists.
The Iran Visa On Arrival is not available for the citizens of the following nationalities :
Here's a map of the visa policy of Iran provided by Wikipedia :