Creating a website briefing document which will be sent out to a shortlist of digital agencies is your chance to pitch your business and invite serious input and feedback about your project.
A well written brief should encapsulate all of your requirements, including creative, marketing communications and any technical aspects. You’ll need to provide some background and reasoning for your requirements which help provide context.
Remember - don’t try and describe the solution. That’s what you want the agency to provide back to you.