The bell is a functionality that allows you to define the sending of a daily mail with the settlements of the previous day corresponding to the assigned services. This appears next to the name of each service, in the Services tab, as long as the user has "Subscription to notices" activated :
The activation of " Subscription to notices" can be done both by the user manager of the entity (from users) and by the user himself (from my space) from the Configuration section.
Once activated, the bell icon will be displayed next to the name of the service and can be activated or deactivated in each case by clicking on it, bearing in mind that the warnings of a certain service will be active when it appears from yellow color: