There are a couple of options available if you wish to add your company logo to the top of your document.
Option 1: Use the "Logo" merge field.
Add the merge field named "Logo" to add an image of your company logo. This image can be uploaded by a Site Administrator for each Organization under the Document Settings tab.
Option 2: Create Header and Footer templates.
Custom Headers and Footers can be created and added to any document quickly.
Start by creating a new template and choosing either Header or Footer. The template will be the same as a regular web template which means you can add both pictures and text to your headers and footers.
Once you have saved the template, you can now use it in any custom template. Go to the General tab of each template and scroll down to the section labeled "Header/Footer". Under Header Template or Footer Template, use the drop down menu to select the template you have created.
Use the additional options to further customize your template.
Header Top Margin - add additional space between the top of the page and when the header begins.
Footer Bottom Margin - add additional space between the bottom of the page and the end of the footer.
Header/Footer Page Setup - control whether the Header and Footer appear on all pages (leave the option blank), all but the first page or only on the first page.