Hi karenb60536875,
There are some PDF types (such as those that are password-protected) that can't be converted. But when that's the case, you'll get a message during conversion, and the conversion will stop. It doesn't sound like that's the case for you.
What happens when you open the converted Word document in Word? Do you see an Enable Editing button at the top of the document? If so, please click that. If you're still unable to select text in the Word document, try triple-clicking to select it.
For reference, I will say that the quality of the conversion depends on the quality of the PDF (see Will Adobe ExportPDF convert both text and form... | Adobe Community). So, there may be cases where a PDF written by a third-party application (a non-Adobe app), may not be written to spec, and that can affect the accuracy of the conversion.
Best,
Sara