Open with the problem you are solving, not your preferred technology. What kind of user will use this, how often, and what happens today? An estimator offshore development center who understands the goal often proposes an alternative that costs less; one who only sees a feature list will price your assumptions along with the work.
Set out the scope as user stories laravel or .net scenarios: a walk through each important path. Equally important, write down what the first release deliberately excludes. An explicit list of exclusions removes more friction at delivery time than any other single page. Indicate as well which items are decided and which are still under discussion — estimators price uncertainty, and pretending everything is fixed only hurts you.
Set out your constraints. The list covers systems you must integrate with, the data you have and application support services where it lives, compliance requirements, traffic expectations, supported browsers or devices and any technology you are committed to. Where a date is genuinely fixed, explain what drives it: a good team will often resequence the work to hit it, provided they hear about it early.
Write down what the word done means feature by feature. Testable acceptance criteria need not use any formal notation: a short list stating the expected behaviour is sufficient. This one section compresses the review at the end by a surprising margin and eliminates most late-stage disagreement.
Finally, ask for a specific format. Request a breakdown by feature or module, the assumptions behind each number, whatever the team considers risky and an optimistic and a pessimistic figure. Treat a wide range as useful information rather than evasion: it normally identifies exactly which requirement is unclear. Then clarify that area and request a revised number — the revised figure is far closer to reality.