Before downloading the app make sure you can see Farsi letters on your mobile phone or tablet.
Can you see the Farsi letters in the next line below?
فارسی صفحه کلید
If you see boxes instead of Farsi letters, your device does not support Farsi display.
Enable Farsi Keyboard
The steps may be slightly different from device to device. This instruction is for Samsung Galaxy S3.
Go to My device (figure 4)
Then tap the Language and Input option (figure 4)
You will see the Farsi Keyboard (figure 5)
Check the box (figure 5)
Using Farsi Keyboard
Start your favorite app(browser, Facebook, messaging, contact, ...) (figure 6)
When you start typing, you will see a keyboard icon on the notification bar on top. (figure 6)
Open the notification window and tap Select input method (figure 7)
Then you can switch between Farsi and English (figure 7)
When you pick Farsi Keyboard, you will see the keyboard (figure 8)
Typing Farsi Letters
Figure 1 show the Farsi letters. Tab the up arrow on the left to see Figure 2
For Figure 3, tab the key at the bottom left corner
You can type English by pressing the letter A on Figure 1
To type connected form of a letter, press the up arrow and click the empty key(ZWJ) to the right of the space key
(typing م followed by the ZWJ yields م)
To type two letters unconnected, press the up arrow and click the empty key(ZWNJ) to the left of the space key is (typing م followed by the ZWNJ followed by م yields مم)
You can use this Farsi Keyboard on any app just like you use the standard keyboard.