Start with the product’s display mode. Personalizable designs use Embedded or Full page. Linked is omitted from their initial publication choices.
Open the product, choose Publish, and look at How customers buy this. On a personalizable product that switch has two segments, not three: Linked is not hidden behind a setting, it is not offered. Storefront modes explained shows the switch and what each mode does.
If the product uses Embedded
The initial Publish screen applies the selected mode’s defaults. For an existing store publication, open its settings and review Appearance, where the Embedded preset and replacement controls live. If Composerie replaces variants, title and price, or add to cart, the theme must not keep a second competing control for the same job. Storefront modes explained lists the three presets and the five overrides behind them.
Under the switch, show preview draws what the mode produces. It is the fastest way to tell a configuration problem from a theme problem: if the preview has the form and your storefront does not, the setting is right and the theme is not.

Then open Make Composerie visible on your store from the setup checklist. Save the app embed and Composerie product block in Shopify, and run Recheck after returning to Composerie.
If the product uses Full page
Full page does not need to fit the editor inside the compact product form, but the product still needs a valid publication and storefront handoff.

Check the product itself
Open the Composerie product and confirm the publish checklist is complete, the expected design is linked, the intended store is selected, and the publication is not still pending.

Finally, open Preview and compare the result. Customer Preview uses the current editor design, including unsaved edits, and disables add to cart. A working preview does not prove that the saved publication or Shopify checkout works. Record any preview error separately from the live storefront error.
Why is Linked unavailable?
The design requires shopper input, so Composerie prevents a publication that would collect no personalization.
Why does Preview work but the live store does not?
Preview can show unsaved editor changes. Check the saved design and publication result as well as the active Shopify theme, block placement, and shop domain.
What should I send support?
Send the Composerie product URL, Shopify product URL, display mode, theme name, and the setup-check result.
Next
Follow fix customizer placement for the detailed Shopify checks.