Android handles custom fonts differently from a desktop computer. Out of the box, changing the system font usually depends on your phone maker. The good news is that most creative apps let you load any font you download.
Using fonts inside design apps
Apps such as photo editors, video editors and graphic design tools can import font files directly. Download the .ttf or .otf file, then use the app import or add font option to load it. This is the most reliable way to use a custom font on a phone.
Changing the system font
Some manufacturers, including Samsung and several others, offer a font setting in the display options that lets you switch the interface font. Support and the way fonts are added vary widely by brand and version, so check your device settings under Display or Fonts.
A note on rooting
Older guides suggest rooting a phone to replace fonts at the system level. Rooting can void warranties and create security risks, so we do not recommend it. Using fonts inside individual apps achieves the creative result without the downsides.
License terms vary from one font to another. Always review the license included with a specific font before using it, especially for commercial work.