All file extensions
.XLSX File
What is it?
XLSX is Microsoft Excel's modern spreadsheet format (an XML-based ZIP archive), used for tables, formulas, and data analysis.
How do I open it?
Opens in Excel, Google Sheets, LibreOffice Calc, or Apple Numbers.
Is it safe?
Usually, but like DOCX it can contain macros, a known way to distribute malware. Only enable macros from senders you trust.
Can I delete it?
Safe to delete once no longer needed.