Use one of the following API methods:
- How to create an order programmatically with
\Magento\Sales\Model\AdminOrder\Create::createOrder()? - How to create an order programmatically with
\Magento\Quote\Model\QuoteManagement::submit()? - How to create an order programmatically with
\Magento\Quote\Api\CartManagementInterface::placeOrder()? - How to create an order programmatically with
\Magento\Quote\Api\GuestCartManagementInterface::placeOrder()?
The proper method depends on your situation, the the detailed decription, implementation and usage contexts of each the methods.