CORE allows you to automatically approve time and expense entries, if required. In such cases, employees do not need to submit their entries for approval. Under Global Settings > Time & Expenses, there are rules that allow you to auto approve time entries for projects and employees. If you have 'Auto approve time entries for projects' checked, CORE ensures that time entries get automatically approved for all new projects. For existing projects, you have to enable the rule 'Auto approve time entries' from the Projects > General > Assignment > Rules screen.
If 'Auto approve time entries for employees' is checked, time entries logged by all new employees are automatically approved. If you want this to apply to existing employees, you need to check the 'Auto approve time' option from the Employees > General > Rates & Options screen. Check CORE Help Center for details on Global Settings.
Note: The Auto Approve options set from the Global Settings screen aren't applicable to existing projects or employees; they are applied to newly created projects or employees. Similarly, if you disable the auto-approve rules, it does not affect the existing entries, but only to the new entries.