For a font to be available in the operating system (Windows, macOS, etc.) and to be usable in programs like Photoshop, MS Word, and others, the font must first be installed.
The fonts themselves are distributed as ttf or otf files.
Example of font installation in Windows 10 operating system
1. Download the font you want;
2. open the file by double-clicking it;
3. In the window that appears, you'll see a small description of the font, its style, and the "Install" button. Click it;
4. Start installing the font, that is, copying it to a special folder where all Windows fonts are stored. You will see the corresponding window with the indicator;
5. When the installation is complete, the "Install" button will become inactive;
6. Open Word, Photoshop or any other program and you will see the newly installed font in the list of available fonts.