Company Logo modification
In order to set up or change your company logo, you have to upload the picture of your (new) logo with the necessary size (max 235px x58px) under the Logos section in Settings>>Company Settings.
PDF Logo modification
PDF logo modification is next to Company Logo settings as indicated above where you can easily save your company logo to be shown in all default PDF templates in your company account. Additionally, you can make kpi.com logo invisible on your default PDFs.
At the last, you can update the company settings in order to save all performed modifications.