OP
OP refers to the server operator, the person who has all privileges/rights/permissions to all actions on the server.
The list of operators is stored in the ops.json file, which is a JSON file located in the server root directory.
Giving players OP and having OP enabled is not recommended for security reasons. Instead, it is recommended to properly set permissions.
It is important to keep in mind that OP players has all permissions assigned by default, including bypass permissions.
Commands
op <nick>- adds a player to the list of operatorsdeop <nick>- removes a player from the list of operators