Damage Notifications is a plugin that tells the people on your server how they take damage. Every time a player takes damage, a message is sent to them in the chat that tells them what type of damage it was. For example, when someone hits a player, the player receives a message that says "You just took ENTITY_ATTACK damage!"

The plugin's configuration file lets you decide which types of damage will send messages to players. See how to edit it here: https://www.curseforge.com/minecraft/bukkit-plugins/damage-notifications/pages/configuration

CurseForge: https://www.curseforge.com/minecraft/bukkit-plugins/damage-notifications