Neil Brown# Microsoft is making Word automatically save new documents to OneDrive by default
LibreOffice Writer doesn't.
And it is free.
And really rather good.
Cross No More
AvocaI looked into this fairly heavily recently, and @neil is right, you need to adopt an eclectic strategy when manipulating .pdf document's.
However, in the end, I concluded, when actually signing legally binding documents, the only really trustworthy thing to do is to print the document and use a pen.
Keep the physical copy, re-digitise it with a scanner and send that copy over the net.
Messy, yes, but at least you can defend yourself if need's be...
Just a thought...