You don’t have to pay anything if a font is free. However, if you get fonts for commercial use, you’ll have to pay a fee. But in whatever way you acquire it, every font comes with a license automatically that gives you permission to use it easily. To license a font, you can go through the End User Licence Agreement (EULA) to learn more about the usage and rights of the fonts. Every font maker and font has different agreements, so it is good to carefully read and understand them before getting your license. Like, some may have limited users, some license may have a time limit, while some may have limited desktops to use the fonts on different devices.