Yes. If you have existing Microsoft® Excel® documents, you can edit them directly from Sheets without converting them. If you’d like to use Sheets collaboration features, such simultaneous editing with your team and targeted feedback comments, you can import Excel files and convert them to Sheets. For more information, see Get started with Sheets.

The following file types can be converted to Sheets: .xls (if newer than Microsoft® Office® 95) .xlsx .xlsm .xlt .xltx .xltm .ods .csv .tsv .txt .tab For more information on importing and converting files to Sheets, see Get started with Sheets. 

Yes, you can download Sheets as other file formats, such as Microsoft® Excel® and Adobe® PDF documents. For a list of supported formats, see Get started with Sheets.

By default, Sheets you create are private to you. However, if you create new Sheets in a shared folder, they’ll have the same sharing permissions as the folder does—anyone who can view that folder’s contents can also view your new document. For more information, see Get started with Sheets.

Sheets keeps all your drafts in one file, along with a record of who made which changes, so there’s no need to keep multiple copies of a file. See Switch to an earlier version of your file.

Yes, as long as this option has been enabled by your G Suite administrator. If it is, you can share any of your spreadsheets with customers, suppliers, and others outside of your domain.