If the specific file type is not mentioned in the search, Google will end up showing the results in all formats. The search results can be narrowed to a specific file type that a user needs by using ‘filetype:’ operator, with a specific format.

To find the exact file type such as PDF, DOCX, TXT, XLS, PPT etc., you can use ‘filetype:’ or ‘ext:’ operator.

For example, if a user needs a company financial results to report the annual reports of Apple in PDF format, so instead of going through all formats and find the exact report, a user can search [apple annual report filetype:pdf] or it can also be written as [apple annual report ext:pdf].

Such a restricted search is usually used by researchers to find detailed related information in a specific format easily, for example, looking a data in Excel, or a power presentation.

In case you are looking for something ‘food prices’ in Excel you should write ‘food prices filetype:xls’