You’ll be able to navigate to your settings to put in the iOS 18 developer beta in case your system runs iOS 16.4 and is used with an Apple ID enrolled within the Apple Developer Program:
- Go to your iPhone Settings
- Faucet on Common
- Choose Software program Replace
- Go to Beta Updates
- Select the iOS 18 Developer Beta
If you cannot see this feature, go to your Settings, choose Privateness & Safety, and allow Developer Mode.