desktop software converts XLSX contact sheets into phone-compatible contact files?

For Android and iPhone imports, you need software that understands both Excel spreadsheets and vCard (VCF) structure. Generic file converters or spreadsheet utilities won’t do this reliably — the format mapping is too specific. Tools marketed as “Excel to vCard Converter” handle the job because they read XLS/XLSX, let you map fields, and output proper vCard files that phones recognize. Softaken Excel to vCard Converter is one such solution with Windows support that’s widely used for this workflow.