Freestyle Libre 2 and 3 come with alarms configured by default. You can turn most of the alarms off by doing the following:

1. Open up the Freestyle Libre App
2. Click on the 3 lines on the top right and then Alarms
   
3. Then you can click on the specific alarm and toggle it off. NOTE in the US can not toggle off the low glucose alarm but can set the threshold to the minimum allowed.
   

The workarounds for the Urgent Low Glucose Alarm, if you don't want it to disturb sleep, are:

1. Turn off your Bluetooth before bed. The simplest solution.
2. Turn the app off completely on your phone
3. Turn off your phone