I tried it on 1.15.2, but I think it should work also on older versions.
Commands:
- /pch clear - clear chat
- /pch mute - mute chat
- /a [Message] - send message to admin chat
- /m [Message] - send message to muted chat
Permissions:
- pch.chat.clear
- pch.chat.mute
- pch.chat.admin
- pch.chat.muted
Also check out my other plugins:
https://dev.bukkit.org/projects/warps-all-in-one-plugin
https://dev.bukkit.org/projects/change-gamemode-through-signs
https://dev.bukkit.org/projects/theory-of-everything
https://dev.bukkit.org/projects/pro-afk
https://dev.bukkit.org/projects/unscramble-protect-your-server