The “featured image” is a thumbnail image that you choose to represent a post or page and appears next to it on your WordPress site. It’s usually best to set the featured image to a picture that sums up that post or page or makes it stand out.
1. From the WordPress Dashboard, click Posts or Pages depending on what you want to set a featured image to.
2. Click the post/page that you want to set a featured image for.
3. Click Set featured image on the bottom right of the screen.
4. Upload the image file that you want to feature by clicking Select Files and selecting the image file on your computer.
5. If you’ve already uploaded the image and have used it in a post or page, it is probably in your media library. In that case, click Media Library on the top left of the window and select your image.
6. Click Set featured image button on the bottom right.
7. Click Update on the right.