We have finished the project and created the .xcarchive file code sign with our client's distribution provisioning profile & certificate. Our client does not have Xcode installed on their computer and they do not have anyone that is proficient in using Xcode. Is there any other way that they can submit to the app store without using Xcode? Like the old way - using iTunes Connect and uploading the zip file? If yes, how can we create the zip file?
Uploading a zip file in iTunes Connect hasn't been supported for quite some time.
Besides using Xcode, the other option is to use the Application Loader application. Log into iTunes connect. Click on Manage Your Applications. Click on the Download Application Loader link. There is also a link for the user guide.