Apple Intelligence not showing in iPhone 15 Pro running iOS 18

The Apple Intelligence beta is not out yet. You will need to wait.

Apple Intelligence Preview - Apple

"Apple Intelligence will be available in beta on all iPhone 16 models, iPhone 15 Pro, iPhone 15 Pro Max, and iPad and Mac with M1 and later, with Siri and device language set to U.S. English, as part of an iOS 18, iPadOS 18, and macOS Sequoia update this fall."

after ios 18.1 my i phone 15 pro not showing apple intelligence

Check your language settings, AI only works for English US at first. Other languages including other English countries could be coming in December.