Application Built

I am looking to have an app built for android and IOS. This would be a survey application that would all us to build out the required fields and have our third-party contractors fill them out. It will require pictures, multiple-choice, static fields, short text, and long text fields. I will need to be able to export the data in csv, excel and PDF. PDF designer forms is a requirement for later use. I will need the app to support up to 300 users to start