Publishing themes
You can add up to 20 themes to your online store, but only one theme can be published at a time. A published theme is the theme that customers view when they visit your online store. Your published theme appears at the top of the Themes page with a Current theme badge. Your unpublished themes appear in the Theme library section.
If you publish a new theme, then your previously published theme moves to the Theme library section. None of your theme changes are lost.
Publish a theme from the admin
You can publish a theme from the admin.
Steps:
After you publish a new theme, your previous theme appears in the Theme library section on the Themes page.
Publish a theme from the theme editor
You can publish a theme from the theme editor.
Steps:
After you publish a new theme, your previous theme appears in the Theme library section on the Themes page.