How to automatically fill checkout data using an order form?

Topic summary

A user is seeking the correct HTML form field names and IDs to automatically populate checkout data on Shopify, similar to how contact forms use name="contact[email]" and id="ContactForm-email".

They reference an app that successfully implements this functionality but cannot use it themselves because their form has additional styling requirements.

The question remains unanswered, with no responses providing the specific checkout field naming conventions needed for auto-fill implementation.

Summarized with AI on November 10. AI used: claude-sonnet-4-5-20250929.

Hello,

Does anyone know the “name” I should use to create a form to fill the data in the checkout automatically?

I mean, for contacts we use name=“contact[email]” and the id=“ContactForm-email” but it was a form for an order?

I know it is possible because this app does it but I can’t use the app because my form has much more styles.