The Application loader is usually located on Mac computers in the HardDrive Xcode folders. If it's not in the Xcode folder you can log in to your iTunes connect account and download it from there.
Note: You must be using a Mac.
To download the Application loader from iTunes connect:
- Log in to your iTunes Connect account.
- Click Manage Your Apps.
- Click Download Application Loader.
- Click the downloaded file to install it on your Mac.