In Visual Composer (or equivalent):
- Create a row
- Add an image as background
- Assign a custom class to the row (example: homepage-parallax-image)
Then, in Appearance > Customize > Additional CSS, paste the following:
.homepage-parallax-image { height: 300px; /* change value as needed */ background-attachment: fixed; background-position: center; background-repeat: no-repeat; background-size: cover; }
Source: https://www.w3schools.com/howto/howto_css_parallax.asp