In your account information you can upload your logo, create your closing text example terms and conditions, and update your address.
You will only need to update this once, as it will be reused for all future quotes.
For the quote itself, you can enter information such as greeting, customer address, 'quote created' date and 'valid until' date. After completing this information, just click on 'Save and close quote header'. That will save the information and collapse the Customer Information section.