Change product price through liquid file in shopify

[Padma20]

I have fetched third-party subscription api  in my product page in shopify. Now I want that the subscription plan price will add with product price and show it in shopify cart. When we go to buy the product, in the checkout page  price should be the total of product price and subscription price.

How can we change the product price not only in ui but also in backend and also the price while we go to buy the product in the checkout page?