What happened to saving documents

A few days ago, i could open a pdf file on my ipad, and save in docuents by clicking the 'wrench' icon, then, i could select it and move it to the appropriate folder.  But, now however, i cannot - the only option i have is 'export to pdf'.  Once i click on that, i immeidatley see the same file on my desk top, but, somewhere along the way, in the last day or two, i cannot open or save a pdf into my ipad documents ...

What happened ...