Open with the business problem, not a list of screens. What kind of user will use the system, how often, and how is the job done today? An experienced team who understands the goal often proposes a simpler way to reach it; a team that receives only the requirements as given will price exactly what you asked for.
Describe the scope as concrete flows: what the user does and cross platform app development company what the system does in response. Every bit as useful, state explicitly what the first release deliberately excludes. A written out-of-scope list saves more friction at delivery time than any other single page. Indicate as well which parts are firm and which are still open — estimators price uncertainty, outsourcing and development insights hiding it helps nobody.
Write down the hard constraints. These include existing systems the software has to talk to, the data you already hold and its condition, security and compliance rules, user volumes, supported browsers or devices and any technology you are committed to. Where a date is genuinely fixed, blockchain development services explain what drives it: an experienced team is usually able to rearrange the plan to protect it, provided they hear about it early.
Say what the word done means for the important items. Clear acceptance criteria do not require special syntax: a short paragraph stating the expected behaviour is sufficient. This one section shortens the review at the end dramatically and eliminates most late-stage disagreement.
To close, say what you expect back. Require a breakdown by feature or module, the assumptions used, the risks the team sees and an optimistic and a pessimistic figure. Treat a wide range as a signal about the brief: mvp development cost it tells you exactly which requirement is unclear. Then rewrite that part and request a revised number — the next version tends to be the one worth planning around.