Shopify order place with api

[Padma20]

In shopify I want to create order through shopify api and mark the order as paid. Now I want that after that it will redirect to the checkout page with amount 0 and there customer will give shipping address and then place order. Here amount 0 means I want to say that as through shopify api it is set as already paid so after redirect to the checkout page the price will be 0 otherwise customer has to pay again. Now I am able to create the order through api and marked the order as paid but after that when we redirect to the checkout page the price is still showing as product price and for this reason customer has to pay again which is not correct process. Actually I want to make the payment in another application and then again redirect to shopify checkout page but as of now I am just testing the process by marking the price as paid through api.

How to implement this feature?