Enable Order merge.

Login as restaurant > Settings > order configurations

Step 1: Enable order merge.

1. Merge Automatically: If you checked this option then order will merge automatically when a customer make an order. it checked the previous order with the same order type, name and phone number, email (if you enabled email). *Previous order must be pending or accepted.

1. Allow customer to select: if you checked it, then customer will get an option to choose merge or make singe order.

Multiple order merge from Order list

For doing order merge with multiple order you have to select order types (COD,Booking,Pay cash etc) or Table no -> then you will get the order select option.