What XLSX is
XLSX is the modern Excel workbook format used by Microsoft Excel since 2007, and it is also opened by Google Sheets, LibreOffice Calc, Numbers and WPS Spreadsheets. Unlike older .xls or plain CSV, one XLSX file can hold many sheets, which suits PDFs with many pages of tables.
What happens when you convert
Each page of the PDF becomes a separate sheet named Page 1, Page 2 and so on. Every text line is placed in a row, and text separated by clear gaps goes into separate columns, so most tables arrive already split into cells. Values are kept exactly as written — as text — to protect IDs, account numbers and leading zeros.
Making the data usable
To calculate with numbers, select the columns and use Excel's Convert to Number option, or in Google Sheets use Format → Number. To combine a table that runs across many pages, copy the rows from each sheet into one sheet and remove repeated header rows.
Common problems and how to fix them
A sheet is empty: that page had no real text — it was scanned; use Image to Excel or OCR PDF first. Columns are shifted on some rows: lines with missing values have fewer gaps; move those cells manually. Dates are shown as text: use Excel's Text to Columns or DATEVALUE to convert them.
Good habits
Compare a few totals with the original PDF, delete header and footer rows you do not need, and save the cleaned workbook with a clear name.