FUNCTION_NAME : function (COMPONENT) {
    var action = COMPONENT.get ('c.APEX_METHOD_NAME');
    var recordId = COMPONENT.get ('v.recordId');
    action.setParams ({
        recordId: recordId // Apex param name : js var name
    });

    action.setCallback (this, (actionResponse) => {
        if (actionResponse.getState() === 'SUCCESS')
            COMPONENT.set ('v.VAR_NAME', actionResponse.getReturnValue ());
    });

    $A.enqueueAction (action);
}