In Molla, we support Product Review App, It’s required and free.
You can download it here: https://apps.shopify.com/product-reviews
How to set up Review in Product Page?
Go to Theme settings -> Product Page -> Enable/Disable “Use Rating product page?”
On a Product Page -> Sections ->Product Single Page–> Content
You can adjust tab position by drag-and-drop function
Result:
Review Form