You can add a school name in two places on the transcript. The first place is above the student information section, which the default says High School Transcript. That field can be edited by clicking on the pencil icon to the right of the wording. Once you click on that pencil, type in your desired heading, then click SAVE. 
The other area can be accessed by clicking on the Settings tab to the right of the Edit tab just above the transcript. Once you click on Settings, scroll down until you see Homeschool Details. You can put in a school name and other information here. Once you have entered the information you wish to enter, scroll down to the bottom of the page and click on Save Changes.
Now, when you print the transcript, that information will be printed on the top right corner of the transcript.