When you use a command, some data is collected and stored in order to detect spam and collect analytics. The following information is collected:
The arguments used with the command
The time the command was used
User IDs of the members in the event
User IDs of members in the event's voice channel (if using karaoke)
User IDs of members who disconnected while muted (if using karaoke)
Options set when using the events module
User IDs and Guild IDs to identify members
Options set when using the leveling module
Options set for customizing the bot in the server
Guilds you are in and basic information about them (partial guild object provided by Discord)
If you would like to request your user data to be deleted, join the support server and ask in the #human-help channel. Note that if you use any bot command your data will be collected again.
Eventcord will automatically delete your server data once it is kicked from your server. However, to make sure data is deleted, join the support server and request data to be deleted.