To start with I got a .ipa file from the development team to test, the developer has mentioned the .ipa file with the device UDID so that I can install it on my iPhone.
if you are unable to execute appium script even after creating a developer team and building the app in Xcode..
Follow the steps given in the below link and try running appium after those steps, I tried it (note: there were some unthinkable libraries missing installation:) and working for me. I am having Mac OS 10.12.5 and Appium version 1.6.5. Hope this is helpful.
Appium Setup for running on real and emulated devices
Run the below command in terminal to open WebDriverAgent project.
Open usr/local/lib/node_modules/appium/node_modules/appium-xcuitest-driver/WebDriverAgent/WebDriverAgent.xcodeproj
Now this will open the WebDriverAgent project in xcode.
If no options are available in development team to select then follow the below procedure to add the account.
a. Click on xcode and navigate to preferences.
b. Click on Accounts.
c. Click on ‘+’ symbol and add the account same as the account used for the code signing activity.
Now you can select the added account in Development Team.