To change the time on your Fitbit Charge 5 will depend on the type of phone device you are using. However, below is the method you can do that.
From the Fitbit app dashboard, tap the Account icon
Scroll down to advanced settings and tap on it.
Make sure automatic time zone (use network time) is on.
Then sync your Charge 3
To change the time format, follow the steps below.
From the fitbit.com dashboard, click the gear icon > Settings > Personal Info.
Under Advanced Settings, find Clock Display Time and select whether you want the time shown in 12-hour or 24-hour clock units.
Click Submit and sync your device.
