The following legal requirements need in order to start a business in Iran.
You may check these links for more information.

Law on the Administration of Free Trade - Industrial Zones of the Islamic Republic of Iran

The Direct Taxation Act

Export - Import Regulations Act

Electronic Commerce Law of the Islamic Republic of Iran

Source:

https://en.mimt.gov.ir/circularinformation/341471-The-Commercial-Code-of-Iran.html?t=Laws-regulations-and-approvals