This is done by using the page style custom CSS setting:



You can select the needed font on this website, for example, take this font:


https://fontlibrary.org/en/font/d-din


If you scroll to USE THIS FONT:




you can see the link code, which has to be used like:


@import url('https://fontlibrary.org/face/d-din');

Then for the needed block, you can add the custom font: