To add/update logo in pricing quotation,
Go to the Admin Portal, and select the login settings in the top right.
Select Account settings, and in the window that opens, scroll down to find the Update Store Logo header.
Click on Select file to add the desired logo image, and your file browser window will open. Select an image smaller than 2.5 MB, and select Open.
Click on Update to save changes. The logo will be add to the top left of your Admin portal screen.
Open your design and generate your pricing quotation. The logo will be present therein at the top left.