A family of Microsoft word processing software products for creating web, email, and print documents.
Desiree, please don't send people to TechNet for questions like this.
Andrei, Word 2010 cannot automatically convert PDF files to Word documents. That feature was first introduced in Word 2013. There is no update to Word 2010 to make the feature available there.
In Word 2013 and 2016, when a client chooses to open a PDF file, the PDF text converter runs automatically (provided that the Advanced option "Confirm file format conversion at open" is not checked).
If the PDF file was created from text (i.e., not a graphic format such as a scan), the result will be an editable Word document. This is called "reflow" in that the page layout is the same as if the document was created within Word; it won't necessarily maintain the same line and page breaks as in the PDF.
If the PDF was created directly from a scan or graphic image, Word will not be able to make an editable document from it. The result will be a Word document containing only images.