I don’t use this feature myself, nor do I read/write Persian, but you can reverse the direction in which characters are displayed in a text frame by using the “Right to Left Writing” function within the “Colour and Effects” section of the “Text” tab on the “Properties” palette - the icon looks like an “R” written the other way round.
However, be advised that this function is fairly simplistic and doesn’t work well in all situations. For example, Roman numeric numbers - e.g. 1002 (one thousand and two) - are also reversed, e.g. 2001 (reads, to LTR readers, as two thousand and one). This may not be a problem for you though depending on what your needs are.