It’s a book in PDF that I’m required to send in docx for submission. I don’t have Word on my computer. Thanks.
Even though there is a way to import PDFs into Writer, and save the result as DOCX, you should consider the correct answer to be no. To check: in LibreOffice, use File → Open, select “PDF - Portable Document Format (Writer)” import filter,
then select your PDF, open it, and try to edit some text.
Seems this is a hot topic:
As @mikekaganski says, LibreOffice is limited when it comes to reliably converting pdf to other file formats. Other tools may work better.
If the PDF contains real text, you may be able to open it in Google doc, and download from there as a Word docx file.
If your pdf contains “pictures of text”, the Lens app from Microsoft or the one from Google may be what you need.
Furthermore, PDF format is designed with focus more on visual reproduction than content structure. Regardless of which tool you use, expect considerable manual labor.