Hey ronm25521515,
As per my understanding, Text Editor is used to edit plain text files only, not PDFs.
In order to edit a PDF, you will need to have Adobe Acrobat.
If you do not have Acrobat installed on your computer, please give it a try and download a free 30-day trial version from the below mentioned link:
PDF creator, edit PDF | Adobe Acrobat XI subscription
Post installation, open the PDF in Acrobat and choose 'Tools> Content Editing> Edit Text & Images' and make desired changes.
Hope the above information helps.
Regards,
Anubha