What is the process of creating an .ipa in case of nonprofit organization?

Hello,

I am new to the Apple ecosystem, and to its development. I am working for a nonprofit organization, where we want to develop a "closed" (only particular users may use it) application for iOS (Android is already done), so I thought we need a .apk like file, .ipa.

The building process of Xcode is returning an error of none of a development team has been selected, and also, lack of provisioning profiles.

What should we do in this case? I guess we need to get a developer membership, but it is not clear for me, since we will not publish it in the App Store.

Also, do I need a physical device (iPhone) to make the build successfull?

Any answer is thanked and appreciated!

What is the process of creating an .ipa in case of nonprofit organization?
 
 
Q