Cross-Platform Mix Selector App

I need a straightforward mobile app that runs smoothly on both iOS and Android. After a secure email-and-password sign-in, the user should be able to pick from ten job-site locations; each location offers ten pre-set concrete mixes plus a simple lime / no-lime toggle and a few extra fields such as slump, air, or any “etc.” notes we decide to add later.

Once the inputs are chosen, the app must automatically compile the relevant data into a clean PDF. Each location gets its own table within that document—no combining—so supervisors can flip straight to the section they need. From inside the app the PDF should be shareable via the device’s native Mail sheet; no third-party accounts required.

Deliverables
• React Native or Flutter source (your choice, as long as it supports iOS + Android)
• Build files ready for TestFlight and Google Play internal testing
• In-app PDF generator with one-table-per-location layout
• Email send function that attaches the freshly generated PDF
• Brief setup README so I can tweak mix values or add a new location without rewriting code

Acceptance Criteria
1. Log-in and log-out flow works with email/password.
2. User can complete the form, generate a PDF, and email it—all in under two minutes.
3. PDF opens correctly on standard readers and shows ten separate tables if data from all locations is entered.
4. No crash or critical bug during a one-day field test on both iOS 16+ and Android 12+.