What is the best file format to use when working with Excel files and uploading them to teams that have heavy in content? I have an issue where a team of users are using an XLS excel file. The file is heavy in tabs, formulas, drop down boxes, charts etc., Excel provides 29 different file types when you save your Excel workbook. When you save an Excel workbook for the first time or use the “Save As” function, you are asked for a folder, file name as well as the file type. By default, Excel suggests the XLSX file type (unless your file has VBA macros)., Excel actually supports saving to 27 different file formats, including CSV, DIF, SLK, and other specialized formats. Additional Details: You will probably choose one file type and stick with it. I've been using .xlsm files without issue for seven years. If you decide on one format, you can tell Excel to always use that file format., Use a font, alignment, format, pattern, border, or capitalization style for column labels that is different from the format that you assign to the data in the range. Format the cells as text before you type the column labels. For more information, see Ways to format a worksheet., Which file format is best for handling extensive data in Excel? It is advisable to use the .xlsx format for managing extensive data in Excel without reaching file size limits., .