There are few font styles available by default in your Samsung Galaxy Grand 2 smartphone. They could be changed by going to Settings -> Device -> Font, which lets you change the font style and the font size. Tap on Font style to change the font, there are 5 styles available where you could choose any.
There is also an option of downloading more fonts, but they are not for free. When you tap Download, it will take you to SAMSUNG apps where there are lots of fonts available.
Here is a screenshot which shows the fonts that are available on the SAMSUNG apps, but none of them are for free they are priced at the cost of Rs.50.
Come back and tap on Font size to change the font size. There are 7 different types of font sizes, depending on your comfort you could choose one. The font size huge will only be applied in specific application where the font size extra-large will be applied in all the applications.