Field service app and booking system.

We have 50 engineers who carry out work for us and would like a new system created for bookings. We would like to develop a company app for apple and android devices, and also look at current process for bookings and build a new system from ground up. We are currently working from a spreadsheet in excel, we add bookings from various companies, which we would then like that data to populate jobs on a field service type app on our engineer’s phones. The app would need to include a form which will create a pdf report and will automatically email that to the back office once work is complete. We would like to keep the excel spreadsheet functionality as this is what we’re used to, so would like the spreadsheet to be the database for app if possible. Also we would like our clients to have access through a portal to see results and confirmed bookings.