How can I stop my iPhone from going directly to voicemail?

Hello!

If your iPhone calls are going straight to voicemail, swipe down from the top-right corner of your phone and make sure Do Not Disturb is off, Focus allows calls, and the Airplane mode icon is gray. If the issue persists, Open Settings, then click Apps, Phone, then tap Silence Unknown Callers and make sure it is off.

Many times this is an issue that needs to be resolved by your internet service provider. I had the same issue and a quick call to AT&T resolved the issue in about 10 minutes. They had to reset something and calls started coming through.