You can customize the Back to top button as you like from Theme Options > Theme Settings. Here from the General tab click Back To Top, and the back to top button field will appear.
Back To Top Button: Hide or Show the Back to top button from this switch.
Custom Back To Top Button: If you switch it off, it will show the default design for the "back to top" button.
Custom Back To Top Button Icon: Select the Back To Top Button icon.
Back To Top Button Background Color: Set Back to top button Background Color.
Back To Top Button Color: Set Back to top button Color.
Keep Back To Top Button On Mobile: Set the Back to Top button on mobile.
Click Save Changes to save theme options. Click Reset Section to reset only this section. Click Reset All to reset all theme options.