Start with the reason this custom automation software development should exist, not your preferred technology. Who will use the system, how many times a day, and how is the job done today? An estimator who grasps the purpose will suggest a cheaper route to it; someone handed only the requirements as given will price exactly what you asked for.
Define what is included as short scenarios: who does what, and what happens next. Equally important, list what the first release deliberately excludes. An explicit exclusion list saves more argument at delivery time than any other single page. Mark too which decisions are settled and which are still under discussion — the difference changes the price, and hiding it helps no one.
Set out your constraints. These include the platforms and software development outsourcing russia services involved, the data you have and where it lives, security and compliance rules, user volumes, target platforms and stacks you cannot change. Where a date is genuinely fixed, say what depends on it: an experienced team is usually able to resequence the work to hit it, but not if the date is a secret.
Say what the word done means for the important items. Testable acceptance criteria do not need formal language: a plain-language note stating what a user should be able to do will do. This one section shortens the sign-off process dramatically and removes the usual argument at handover.
To close, say what you expect back. Request a breakdown by feature or module, a written list of assumptions, whatever the team considers risky and a range rather than a single figure. Read a wide range as information, node js vs laravel performance not evasion: it tells you the part of the brief that needs work. Then tighten that section and ask again — the revised figure is much more reliable.