Clarity PPM 15.x
This option is available as from Clarity PPM 15.8.1 version.
Follow these steps:
1. In Clarity, click Administration, and then click System Settings.
2. Under Header Logo, click Upload New Logo to upload the new header logo.
This logo will appear on a white background color. Hence, we recommend a dark color logo. The height of your logo should be 24 pixels and it can have a maximum width of 240 pixels.
More information can be found on the Documentation:
Clarity PPM 15.8.1 Release Notes
Clarity PPM 15.8.1 System Settings
For instructions to modify the Icon on the classic UI, follow the steps on this KB article: