Tablature is a very old style of notation of music for Instruments especially but not only stringed and fretted. It is a notation which shows the player where to place the fingers rather than which notes to play. In this repect it is infelexible because it is instrument specific however it requires no additional skills such as reading music score does.
It has the advantage of being easy to write down as it follows the stringing of the instrument with a number written on the string corresponding to the fret to press. This can be achieved in normal word processing without any special font or notation. The only proviso is that the font should be non-proportional e.g. Courier.
There are also several programs which will take in a proprietry music format including abc and produce a tablature for any specified instrument or tuning. E.g. TablEdit and Bucket O' Tab.