Open with the reason this custom software development services should exist, not a list of screens. Who will use it day to day, how many times a day, and what happens today? An estimator who knows what you are trying to achieve can propose a simpler way to reach it; one who only sees a list of screens prices your assumptions along with the work.
Describe the scope as short scenarios: a walk through each important path. Equally important, write down what the first release deliberately excludes. A written out-of-scope list removes more argument later than the rest of the brief combined. Indicate as well which parts are firm and which are still open — honest teams price those differently, and pretending everything is fixed only hurts you.
List the constraints. This means the platforms and services involved, the data you have and where it lives, security and compliance rules, expected load, which devices matter and any technology you are committed to. Where a date is genuinely fixed, hire developers in saudi arabia say why: an experienced team will often cut the right scope to protect it, but only if they know it exists.
Say what the word done means for the important items. Acceptance criteria do not require any formal notation: a plain-language note setting out what must be true when the feature works will do. This single habit shortens the sign-off process considerably and eliminates most late-stage disagreement.
To close, ask for a specific format. Ask for a task-level breakdown, a written list of assumptions, whatever the team considers risky and an optimistic and a pessimistic figure. Read a wide range as information, not evasion: kotlin software development company it tells you where your description is thin. At that point rewrite that part and request a revised number — the next version is far closer to reality.