'para' is a 'preposición', in spanish a 'preposición' express a relation between two words or expressions. For example:

* Mañana voy para mi casa. (Tomorrow I go to my home)

In this case 'para' express direction.

* Esta carta es para mi mama. (This letter is for my mother)

In this case 'para' express a purpose o use of something.

* El computador estará listo para mañana. (The computer will be ready tomorrow).

Here 'para' express time.