Any help for my iPhone falling in water

Take it to an Apple Store or Authorized Apple Service Center. Let them assess it and advise you how to proceed.

Voicemail cannot be retrieved on an iPad.

You can likely retrieve it from a landline telephone or other telephone by calling your iPhone's telephone number and then entering a code (perhaps an asterisk??) and then your voicemail password. The specifics depend on your cellular carrier.

I should have been more clear ...

Call your iPhone's number from a landline or other telephone. Wait for your voicemail greeting to begin. Once it begins, then enter the code (likely an asterisk - possibly a number sign, but I don't think so). Then you should be prompted for your voicemail password.

Stop sending me emails cuz I have over 6000 of emails just from apple support) I am handicapped and very disabled and I can’t erase all of them! Tell me a shortcut !!

Best of luck!