It doesn’t give me the option to set up a voice mail
It doesn’t give me the option to set up a voice mail
[Re-Titled by Moderator]
iPhone 8 Plus, iOS 13
If you mean visual voice mail, then see the article:
Set up Visual Voicemail on your iPhone - Apple Support
If you mean your actual voice mail, then that is a service provided any your carrier service. You will need to contact your cellular provider for help.