You need to be online and signed in to use Google Docs. However, you can download your documents, spreadsheets and presentations, work on them offline, then re-import them to Google Docs.
You can export a spreadsheet in several different file formats, including .xls, .txt, .csv, .pdf, .html, and .ods. Note: it's not possible to export a spreadsheet as .xlsx.
To export a spreadsheet, just choose File > Export and select a file type.

A few tips to keep in mind as you export:
- .txt - In this format, you can only export a single sheet.
- .csv - If you choose .csv, the file will export in UTF-8 and will not open directly in Excel or other applications. To edit a .csv file in Excel, open Excel, select File > Open, and then browse for your .csv file.
- .pdf - This is the best option for printing spreadsheets when formatting and styles are important. It's a good alternative to the Print menu option. There are many options available when exporting as a .pdf:
- Export one sheet or all sheets in a single spreadsheet.
- Adjust the size to 'fit to width' or 'actual size.'
- Choose either a landscape or portrait layout.
- Select your paper size - Letter, Legal, or A4 (standard for most European printers).