Start with the reason this software should exist, not a list of screens. Which people will use the system, how often, and what happens today? A vendor who knows what you are trying to achieve can propose a cheaper route to it; one who only sees a list of screens will price exactly what you asked for.
Define what is included as user stories or scenarios: who does what, and symfony vs spring what happens next. Just as important, list what you are not building. An explicit list of exclusions prevents more argument later than almost anything else in the document. Indicate as well which decisions are settled and which are still open — estimators price uncertainty, and custom laravel development hiding it only hurts you.
Set out your constraints. The list covers existing systems the software has to talk to, existing databases and their quality, security and compliance rules, expected load, target platforms and infrastructure that is already decided. If a deadline is real, explain what drives it: an experienced team can often cut the right scope to hit it, but not if the date is a secret.
Write down what the word done means feature by feature. Acceptance criteria need not use any formal notation: a plain-language note describing the expected behaviour is sufficient. This single habit compresses the review at the end considerably and eliminates the usual argument at handover.
One last thing, say what you expect back. Require a task-level breakdown, the assumptions used, whatever the team considers risky and an optimistic and a pessimistic figure. Treat a wide range as information, not evasion: it normally identifies the part of the brief that needs work. From there clarify that area and ask again — the second estimate tends to be much more reliable.