Apple is not here. You won't get a direct answer from Apple in these forums.
Not sure what issue you seem to be having, but it does not appear as if its something that is generally wrong on many peoples devices that Apple can find and fix. It may be something specific to your setup or a glitch that would be almost impossible to actually fix. Most glitches would get resolved by simply restarting the devices
Its also possible its a feature called "Calls on other devices". If your iPhone and iPad are using the same Apple ID, and you have the "Calls on Other devices" setting turned on your iPhone, and you have the "Allow calls On" option turned on there as well for your iPad, then calls received by tour iPhone will also ring on your iPad and you can answer them there. Is it possible that is what you are hearing? This is a feature, not a an issue to be fixed. The ring tone on your iPad may sound like an alarm if that is what you have it set to
You can change it in in Settings ➜ Sounds ➜ Ring Tone
click here ➜ Make and receive phone calls on Mac or iPad - Apple Support