If you still use the Deliveroo tablet
It is possible to automatically accept orders on the Deliveroo tablet. For this to work, leave the Deliveroo tablet turned on. View this article from Deliveroo for more information.
If you no longer use the Deliveroo tablet
If you use a POS: Configure your POS to automatically accept the order.
If you use the Delivery Manager App: Activate the Automatically accept orders toggle found on the Orders tab of the Settings page.