How to make payment in Iran?

As you need credit cards(Master, debit, Amex) are not accpeted in Iran, You can bring some cash with you and use local exchangers to exchange them to Iran Rial, Almost all currencies are accpeted ,But US dollar is the best shot.
carrying too much cash with you is not wise, The good news is you can buy Iranian gift cards which are like prepaid debit cards, it's called" Karte Hadieh" in Farsi. The best option is to use  these cards in Iran, The banks sell them for the amount they are worth and  you can buy them for any amount you like and of course you will pay the same price as the face value.
The gift cards are accepected in almost all the stores, restourants, hotels withing the country.
When you need cash, You can easily go to an ATM machine and cash them, Just keep in mind that you can only get 2000,000 Iran Rial ( almost $70 USD) Per day.
The best thing about these gift cards is that they have password, And only the card owner can use it, If they got lost or stolen, You can simply  contact the issuer bank and ask them to freeze the money , and get a new one