You can use the WordPress editor to customize your site background.

1. Sign in to WordPress.
2. Click Appearance from the Dashboard, located on the left side of the screen.
3. Click Customize.
4. Click Background Image, depending on your theme customization options.
5. If there is already a background image, click Change Image. If there is not already a background image, click Select Image.
6. Click the image you want to be in the background of your site.
7. Click Choose Image, located on the bottom right corner.
8. Click Save and Publish, located on the top left corner of the page.
9. Click X, located on the top left of the page, to return to the Dashboard.