You can simply customize the text of your button on the “Customization” page.
Follow these steps to customize your button style and text:
On your restock panel Select Personalization.
From the “Notify me“ widget section select the Product page.
Select Button or Form to be added to your store. You can also have the float button by selecting the Show float button option.
Click on Personalize.
You can customize Button text, Background color, Text Color, Border color, Border radius, and Border size.
You can use your CSS skills to do more advanced customizations from the Advanced section.