Microsoft Advertising Editor allows you to work and edit campaigns online and offline because it is a downloadable software that doesn’t require an active Internet connection. However, you have to sync your Microsoft Advertising Editor with your Microsoft Advertising account first before you can edit campaigns online. This Sync requires an active Internet connection. After the sync is done you can edit your campaigns while being offline.
This question is a part of the Microsoft Advertising Certified Professional exam. You can find all the answers with detailed explanation for this exam in the Microsoft Advertising Certified Professional exam page.