Number of rings before going to voicemail on iPhone 15
How do I set number of rings on iPhone 15 before it goes to voicemail?
iPhone 12, iOS 18
Contact your cellular carrier. They are responsible for call handling and voicemail. If they have the ability to lengthen the time before a call goes to voicemail, they would have to adjust it. It isn't the number of rings, it is based on time for the call setup.