Cannot Edit Text in Pages (on my Macbook Air)

Help!

I created a few documents on my phone, in Pages. I then transferred them to my Macbook Air and could edit them just fine. A few weeks later, I went in to edit them, and I cannot edit ANY of them. On top of that, I only have the ability to export it as a PDF and cannot convert it into Word.

What has happened? Has it locked (somehow)? Have my editing abilities timed out? How can I restore the editing abilities of the Pages documents?

Thank you.