The steps depend on which version of the app you're using.
If You're Using Magical Preorder (the new version):
Badges appear on product images on your home page and collection pages to show preorder status.
In the app, click Settings.
Scroll to the Badges section.
Badges are enabled by default. To turn them off, uncheck Enable badges.
Edit the badge text for:
Active products (available for preorder)
Preview products (coming soon)
Click Save when you're done.
Changes apply right away.
If You're Using Preorder Pro + Back in Stock (the legacy version):
To enable and customize product badges:
In the app, click Settings from the left-hand menu.
Click Preorders in the dropdown.
Under Product Badges, toggle Enable Badges on.
Customize the badge text, color, and font.
Scroll down and click Save in the bottom-right corner.