How to set Fastest Shipping option as default?

Topic summary

Goal: Default the fastest shipping rate (e.g., “DHL Next Day Delivery”) at checkout instead of the cheapest option for the holiday period.

Proposed approach: Use custom JavaScript to auto-select the desired shipping method at checkout.

  • Example code: On DOMContentLoaded, iterate over input[name=“shipping_method”] and set checked=true for the option whose value includes the target label (e.g., “DHL Next Day Delivery”).
  • Steps suggested: Online Store → Themes → Edit code → add the script in checkout.liquid or a theme JS file (theme.js/custom.js/scripts.js/app.js).

Hurdles: The store owner cannot find checkout.liquid or typical JS files (theme.js, etc.). After being advised to look in Assets for JS files, they still do not see any of the suggested filenames and requested a pointer based on their asset list (shared via screenshot).

Artifacts: Images show the current checkout shipping options and the Assets file list.

Status: No confirmed file location or implementation; no verification that the script works. Discussion remains open with unresolved next steps.

Summarized with AI on December 16. AI used: gpt-5.

Thanks for replying @rajweb !

Yes unfortunately I don’t see a checkout.liquid or theme.js in our theme. I don’t know which is a similar file I can put this code on (lol). Do you have more details on how I can do Step 4, please?