The file extension OTF features an OpenType font, a font standard for computers that was originally developed by Microsoft and later developed jointly with Adobe. Released in 1996, there were already a large number of OpenType fonts by the year 2000.
Fonts are in short all alphanumeric characters, special characters and partly international characters represented in a specific style and cut. Well-known fonts are for example Arial, Helvetica or Times New Roman.
An OTF file contains data in a tabular format, which includes either a TrueType or a Postscript Outline Font (in the so-called CFF format). OpenType fonts can have the endings orf and the file ends ttf, depending on their content. Often, the suffix ttf is used to maintain compatibility on systems that do not natively support OTF.
While font files that only contain Postscript fonts usually have the ending otf, font files with TrueType data can have both endings.
OTF fonts can be easily viewed and installed in Windows by double-clicking or using the shortcut menu, they are then automatically copied to the fonts folder and are immediately available. On the Mac (as of OSX) there are several fonts folders that can contain fonts. (eg System / Library, Library) To install, just copy the OTF file into one of the fonts folders or use the font collection.
Although OpenType is a registered trademark of Microsoft, the technology is available to all and may be used on any operating system. In addition to Windows, Mac OSX and Linux also support the OTF standard through the open source project Freetype. Since Font Rendering is an operating system function, all programs that fall back on it can automatically use OpenType fonts, but some programs can not access all special characters.