Flutter and PHP Developer Needed

We have developed an Android App on Flutter. We have made its 4 Panels, (Customer and Delivery Boy Panel on Android) and (Admin and Merchant Panel on Web using PHP). We purchased this code online. There is a problem in the code, where we have to make signup for merchant through admin panel only (which is very difficult always because then we need to update merchant's latitude and longitude on Google map through admin panel only)

But we want you to add Signup page on Merchant Panel Web page and integrate Google Map API in it (Which is integrated on other remaining panels).
We want you to add some other fields in the merchant panel and make it functional with other panels.)