Validate and submit ipa to AppStore without source
You must build for device using the appropriate certificate/provisionning,Then go to products, you find the .app file, choose "show in finder"Zip the .app file and send it to your client.
Once you've done this, your client must use "Application loader" to submit/updload the binary/application.
"Application Loader" is an utility installed with Xcode.
In general you find it in the path "xcode/Applications/Utilities"
Your client could use the application loader to upload the ipa.
You should first select Deliver Your App and not Open Package which is misleading.