If you pick Options|Font from the menu, a font selection window will appear. Select the font you want to use and click OK. You can also select a recently used font from the Options|Font submenu.
The font setting applies to the entire file. It only changes the way it is displayed. EditPad is a plain text editor. It does not support any text formatting.
Changing the font via Options|Font only affects the active file. In EditPad, the choice of font is part of the text layout configuration. That is the combination of settings that determines how EditPad displays text. The default text layout configuration can be set for each file type in File Types|Editor Options.
If you want to edit text files in a language that uses characters that are not used in English, you will need to select the correct "script" from the drop-down list near the bottom of the font selection window that appears when you select Options|Font from the menu. Not all fonts support all scripts. Particularly scripts like Arabic, Chinese, Japanese or Korean are often supported by few fonts. If you can't find any font with the script you want, you will need to install them from your original Windows CD. You can do so by clicking on the Windows Start button, choosing Settings, and opening the Control Panel. Among the Regional Settings, there are options for enabling support for complex scripts and ideographic scripts.
Some fonts have "Unicode" in their name. Such fonts include "Arial Unicode" and "Lucida Sans Unicode". These fonts contain all characters in all languages that Windows supports. If you use one of these fonts, you never have to worry about using the right font for the right language.
Fonts with Chinese, Japanese and Korean characters are available in two variants: the regular variant (e.g. MS Mincho), and a rotated variant for vertical printing (e.g @MS Mincho). The rotated variant always has the same name as the regular variant, but with an @ symbol in front of it. In Options|Font, you should select the regular variant, so characters will appear upright on the screen. In the print preview, you can select the rotated variant if you want. If you print with the rotated variant, the text will appear printed vertically if you rotate the printed sheet of paper 90 degrees clockwise. If you print with the regular variant, the printed text will flow from left to right, like you edit it in EditPad.
Options|Configure File Types