How to use Appuploader to submit and upload iOS applications:

How to use Appuploader to submit and upload iOS applications:
Select IPA and Channel: On the submit upload page, select the IPA file. There are four available channels in the upper right corner: 1, 2, 3, and 'Old Channels'.
Set a dedicated password: Set a dedicated password for submission.
Upload IPA: Start the upload process by selecting the IPA file.
After successful upload, you will receive a feedback email from Apple containing further instructions.
Submit upload interface: This interface is mainly aimed at users who have already paid $99 to Apple. The free account cannot access this feature and will see a red circle prompt: "Your account has not yet paid Apple $99. You can only create a development certificate and cannot submit or upload for distribution. You cannot use Apple to log in, pay, or push notifications." Simply put, this means that the free account can only use the software for internal testing and cannot publish applications.
Note: If the submission fails due to firewall issues with your internet service provider, you can try using the 'old channel' or switch to a mobile hotspot or VPN.