While not everything you write in this early stage will end up in your final document, it will help you formulate your knowledge and refine how you articulate that knowledge.
The actual research, whether experimental work, theoretical modelling or even literature reviewing, is a significant part of the pre-writing work that goes into a document. The various ways of finding and gathering material and the critical assessment of information, for instance, obviously affect the text. We encourage you to consider this early stage to be part of the writing process. At this stage you might be writing any of the following: notes, lists, journals, blogs, email, the list goes on. These different writing activities are an important part of creating and articulating knowledge, which in turn helps inform your later writing processes. See the section Using information for more details on using texts and referencing.
Make absolutely certain that every single source of information is well-documented; author, title and bibliographic information down to specific page numbers must be available for anything that is included in the text. It will also save you time and stress later in the writing process.