In school history settings, a document-based question (DBQ) is an essay or short-answer set where students use their own knowledge plus evidence from provided documents.
DBQ Online is a school platform/login product, and The DBQ Project describes DBQs as historical inquiry/document analysis and evidence-based argument writing.
If you were actually searching for VA disability DBQs, go to the VA DBQ section.
DBQ Online states users should go back to their school portal to log in (for example via Canvas, Clever, or Blackboard).