All teacher documents were originally created in Microsoft Word and some were saved as Web Pages. Those may be easily copied and pasted back into Word for making any changes desired.
However, some of the files don’t translate back into Word that well. So, some files are in Word only. Where files are in both htm or html and Word you can click on the Word icon after the link. You can save the Word files in Word and make any changes you want.
If you don’t have Microsoft Word, you can get Word Viewer or download the free LibreOffice to open and edit the files.