Scroll to Top is a button at the bottom left or bottom right corner of the website which when clicked will scroll up to top.
You can find the Scroll To Top option in the Customizer on Appearance → Customize → Footer → Scroll To Top

Customize Scroll To Top Button
- Show Scroll To Top Button: Enable or disable button.
- Visibility: used to hide or show the scroll to top button on devices.
- Icon: Set icon for button.
- Position: Where button will display: Bottom left or bottom right.
- Display:
- Static: displayed at the very bottom of the page.
- Sticky: visible as user scrolls down through the page.
- Margin bottom.
- Margin right.
- Styling: Advanced styling settings for button.