Install the Fitbit app from the App Store
Open the Fitbit app and sign in or create an account
Turn on Bluetooth on your iPhone
Make sure your Fitbit device is charged and nearby
In the Fitbit app, tap the profile icon
Tap Set Up a Device
Select your Fitbit model
Follow the on-screen instructions to pair the device
Allow Bluetooth, notifications, and other requested permissions
Keep the Fitbit app open during setup
Wait for the sync to complete
Open the Fitbit app regularly to sync data
If needed, pull down on the app dashboard to force a sync
Restart your iPhone and Fitbit if syncing fails
Update the Fitbit app and iPhone software if needed
Unpair and reconnect the Fitbit if problems continue