Check Apple’s official Beta Software Program page
Sign in with your Apple ID
Enroll your device in the iOS beta program (where available)
Back up your iPhone to iCloud or your computer
Install the beta profile (if required) from Apple’s instructions
Go to Settings → General → Software Update
Select the iOS 26 beta update when it appears
Tap Download and Install
Accept the terms and conditions if prompted
Keep the device on Wi‑Fi and plugged in during installation
After updating, verify the version in Settings → General → About