I want to implement the Invite User actions located in the Calendar>Events to Project.
I've tried searching in the Workflows and other settings but I couldn't find where is the actions located.
Invtite Users does not have any UI for configuration. you have to modify the following files for your customization.
modules/Events/models/Module.php | function -> saveRecord | Between lines -> 28-40 modules/Events/models/Record.php | function -> getInviteUserMailData| Between lines -> 136-189 modules/Calendar/CalendarCommon.php | function -> sendInvitation| Between lines -> 150-181