Step 1: Under any of your courses, Click the Price tab then click Checkout Design
Step 2: Click the Edit Button on the upper right and then click the button you want to edit.
Step 3: In the sidebar on the left, you can edit the following settings as desired:
Button Color: Select the desired button color.
Button Text: Enter the desired button text.
Step 4: Click Save or Save and Exit.
Step 5: To preview the buy button, click Preview Check out.