To show the product customization button on your product page, you need to enable the Customize it button option on your theme. Please follow the steps below:
- Go to admin -> Themes page.
- Click Customize button on the top right of your main theme.
you will be redirected to the theme editor page.
- On the theme editor page, click the theme setting link. You can find it on the left side of the page.
- The theme setting area will be showing up on the right side of the page. Click the App Embed Menu tab you will see an option entitled button-customize. Click the toggle button to enable the option
Save the theme. customize it button will be available on your product page.