Step 1
Open iOS project into xcode.
Step 2
Go to Product menu and click Archive.
Step 3
Go to Window menu click Organiser, you can see archived app file there.
Step 4
From right panel Archive Information panel click Export.
(Exoprt option only available if you have valid Apple developer program account.)
Step 5
From popup window check Save for Ad Hoc Deployemnt and click Next.
Step 6
Now select Development team provisioning profile which will be same used for signing the app(build)
and click Choose.
Step 7
From device support popup check Export one app for all compatible devices
and click Next.
Step 8
On Summary popup click Next.
Step 9
Enter name for ipa and folder location to save file and then click Export.
Summary:
xcode > open another project > product > archive > organiser > export > save for ad hoc deployment > choose provising > devic support > App summary > export