iOS isn’t that complicated so every option, that you wanna change can easily be seen on their settings. You might not be the iPhone geek or didn’t play much with you iPhone and have a weak eyesight then follow these few steps below to increase font size on iPhone that could be compatible to all iPhone officials and third party apps like note and etc.
To change font size on old iOS you need to go to setting, then general and then go accessibility tab where you can find Large Text option.Refer images below:
For the newest iOS7 it’s slightly different. First you need to go to settings, then general and then open text size option.
I hope you understand this small iPhone tutorial and if you want to change text style and etc then you can try any app from iPhone library. For more other cool iPhone tips go here.