Ensure you have Java installed (older versions may be required for legacy apps). Double-click the JNLP file. If it doesn’t open, right-click > Open with > javaws (Java Web Start).
Converting JNLP to PDF can be challenging because JNLP files are designed to be used with Java applications, and they may contain complex data that can't be easily converted to PDF. Some common challenges and limitations include: convert jnlp to pdf
Before installing make sure to follow these steps given below
Make sure you have backed up your device using iCloud or iTunes on your PC or Mac. Otherwise, you may lose your data.
You can connect your device using a Lightning or USB-C cable to your PC or Mac.
On your device, go to Settings - [your name] Find My - Find My iPhone/iPad, then turn off the Find My iPhone/iPad.
In iTunes or Finder (Mac), hold down the Shift key (or the Options key on a Mac) and click on Restore iPhone... button.
After iTunes has installed the .ipsw file on your device, follow the on-screen instructions to restore your data.