A logo is always displayed at the top of the page. If you add a banner, the logo is displayed right under the banner, above the page title & description.
If you don't add a logo to this page, Whispli will automatically include the Organization logo defined in the Organization settings (more on the Organisation Settings here).
To add a logo, just go the page configuration by clicking on 'Pages' in the left menu, then on the page title you wish to update:
and click on 'Add logo'.
The logo must be at least 200 x 100px. It can be a PNG file or a JPEG file. Just select the file from your computer. As soon as it is uploaded, it is displayed at the top of the configuration page and immediately visible on your page.
If you wish to update a logo, just click on the cross at the top right of the logo to delete it from the page. If you don't replace it, the system will automatically display the Organization logo.