Pages can display a dropped single PDF page and cannot edit that new document object based on that PDF. You would need a dedicated (and paid) PDF Editor to clean up extra tabs in your PDF. Apple's Preview or Adobe Acrobat Reader are not PDF editors and cannot repair those extra tabs.
The best bet is to clean up the tabs in the source word-processing document from which you created the PDF and then regenerate it. Failing that, if you have MS Word v16.31 or later, you can open the PDF in Word and it will convert it to Word DOCX. Now, you can remove the extra tab characters and then Save as PDF again.