It'a a great ides to create such an app where user can request for the courier to pick the things from home and for courier's members, they pick up the couriers from user's home.
From your requirement, our understanding is that, there will be two parts in the app, Ist one for the users and 2nd one for the courier's members.
When app will open, we are planning to give two options on the first page that is "Courier service provider" and "User".
User part,
We are planning to create a login page for the users, where users can login, we are assuming that there will be a form to contact the courier service providers, users can fill up that form with location or there will be some predefined location or area where courier service providers will work.
Courier service provider part,
We are planning to create login page for Courier service provider also, we are assuming that they receive the notification in the app that some users want to contact, then they contact with the users and pickup the couriers.
There will be also be a website that carry the same functionality as in the app. We will have to create some web services for the login for users as well as for service providers, submitting form to contact courier service providers.
We have few queries that help us to proceed further with app.
a) Do you have the designs of the app or any wire-frame so that we can understand the flow of the app.
b) We have both developers Php or .net developers which one will you prefer?