Accent: According to the Longman Dictionary, A particular way of speaking which tells the listener something about the speaker's background.
Since everything differs massively between English and Persian, it is very hard to try and show Farsi pronunciations and accents through English text and words.
Many foreigners believe that Tehrani accent is the main and most used one in Iran, but that is far from right. If we want to point out the main accent, it would be The Main! yes, that's right. This is the actual name of the accent, and it is used in media and it is the accent that would be heard the most if you were to spend a day throughout anywhere in Iran.
Make no mistake, it is used massively in Tehran, but it is not "Tehrani" accent. What people, even some Iranians mistake for the Tehrani accent, is a way of talking that is free of any type of ethnical or regional casualties. But Tehrani accent is full of differently spelled words and phrases.