The most common need for macros in Write is to manipulate text - add text, change fonts, copy text and so on. There are two main objects that can be used for dealing with the text of a document:
The Text collection - gives access to the entire text of a document
The Selection object - gives access to text, fonts, paragraph attributes, tab settings and styles of the current selection
For some tasks (inserting text, deleting text) you could use either the text or the selection object. If you want to specify any font or paragraph settings, the Selection object must be used. If you want to check the entire text of a document for a particular word then the Text object is the one to use.
There are also objects and collections to allow you to manipulate (create, open, print) documents - see Working with documents.