Start from a bounded query
Use a saved query or a clear project, area, iteration, state, or work-item-type boundary. Export only fields needed by the review, but always retain work item ID and revision. A broad enough query can also hit Azure Boards' own 20,000-item cap with no error shown; see why Azure Boards queries truncate at 20,000 items before trusting a large export as complete.
Preserve types and identities
- Write dates as Excel dates and numbers as numbers.
- Keep reference names and IDs where an import must resolve users or relations.
- Record the Azure DevOps revision for conflict detection.
- Keep choice values exactly as the process defines them.
Make the workbook reviewable
Use a table with frozen headers and filters. Put instructions and validation results away from the raw data table. Before sharing, remove fields reviewers should not edit and confirm the workbook contains no unnecessary sensitive data.
Setting different values per item?
Azure DevOps' own bulk-edit panel only applies one value to every selected work item. See giving each work item a different value in one pass if that's why you're exporting in the first place.
Export a typed workbook in Azure DevOps
Excel Import & Export for Azure Boards creates an editable workbook and retains the metadata required for validated re-import.
See Excel Import & Export for Azure Boards