How to pass key data from hydrogen to shopify?

Topic summary

Seeks a method to capture custom user form input in a Hydrogen (Shopify’s React-based custom storefront) app and pass/attach that data to the Shopify backend at purchase so it’s available for order fulfillment. The poster is unsure if metafields are appropriate for this use case and requests guidance; no solutions or outcomes yet, discussion unresolved.

Summarized with AI on December 25. AI used: gpt-5.

Hey, I’m creating a Shopify store for a client which requires information from the user so that the client can fulfil an order. Essentially I need to gather form input on hydrogen and then pass this to my Shopify backend whenever a product is bought, how can I do this? I’ve looked into metafields however I’m not sure this solves my problem. I’m using Hydrogen to do this. Any help is appreciated, thanks.