Guide

1. Go to Setup in the top right corner.

2. In the Quick Find box, enter Themes and Branding and select it.

3. Create a New Theme.

4. Provide a Theme Name.

5. Locate the Brand Image under the Branding section and upload your company logo image file from your computer.

6. Ensure the image size and format meet Salesforce's recommendations (usually JPG, PNG, GIF, and specific dimensions). Hit Save.

8. Make sure “Use brand image on Lightning Experience” in toggled ON.

9. Hit Save.

10. And finally hit Activate.