Listed all Windows and macOS support IPA on this page.
Once downloaded IPA to your Windows or macOS, you can use AltStore and Sideloadly method to sideload IPA files.
Also, you can use the Without PC ( Online ) method to sideload IPA files.
iOS 14 to 14.8.1 Jailbroken users now can sign Jailbreak IPA permanently with the Permasigner tool. The Permasigner tool was tested with Unc0ver Jailbreak / Odyssey Jailbreak / Taurine Jailbreak tools.
Note - The Permasigner tool only works with jailbroken Devices. Make sure to jailbreak your Devices first with the below jailbreak tools.
How to use Permasigner - Install Guide
TrollStore is another method to sign IPA files permanently. The TrollStore supports both Jailbroken and non-jailbroken Devices.