Go to Settings > Company info. If you have Subsidiaries turned on in Settings > Addons, the Company info menu will be replaced by Subsidiaries.
This is where you can add the billing address of your company or change the default logo. This logo is going to be used in your PDF exports across Productive.
Formats supported for the company logo are standard image formats - jpg, png, jpeg. GIFs are not supported and although they may appear here, an error image will be displayed on invoices.