TypoScript functions can be considered as a set of common properties. Whenever an object has a property corresponding to a given function, you are assured to have that set of properties available.
This chapter gives you a brief overview of the most common functions available in TypoScript. As always the TypoScript Reference is the ultimate source of knowledge on the matter. For each object property, it indicates whether it is a simple data type or a function.
The most used function is the "standard wrap", usually known as "stdWrap". Due to its importance, it is entitled to its very own chapter.