QUICK ANSWERStart with the tool that matches your immediate input.
Open Spreadsheet Formula Viewer first when its stated purpose matches the result you need now. Use XLSX Viewer only when it solves a separate next task.
This guide is for writers, office teams, students, and data workers. Start with Spreadsheet Formula Viewer when your immediate task is to inspect your input with the Spreadsheet Formula Viewer and review a clear, useful report. Move to XLSX Viewer only when you also need to inspect your input with the XLSX Viewer and review a clear, useful report.
The goal is not to run two tools automatically. It is to finish the first narrow task, inspect its result, and then decide whether XLSX Viewer solves a genuinely different next step.
Both tools sit in Documents & Files, but they handle different inputs or outcomes. Keeping those roles separate reduces repeated work and makes verification easier.