Windows for decades used the file extension as a hint of the file type. If you change that, the association to the matching app is lost. This differs on say, Apple's File System.
So no, you can't change the last .pdf without losing what app it opens with.
At the same time the NTFS (what that is, is on the web) does not supply a "completed" file attribute so that column is non-standard. Your app or extension will define what that column does.
So for now, until you catch up on file names, just leave the file extension alone and rename the file as you see fit.
Hello, I have two questions.
1. My first question is how to mark individual items in this folder as "complete" for the purpose of sorting using the last column on the right.
This may be related: My windows is not letting me edit the details pane when I right click files and go to property>details. How can I fix this?
2. My second question is whether I can append a common suffix or prefix to multiple file names all at once. For instance, append the same prefix to the start of each file name (while keeping the rest of the file name intact), or append a suffix to the end of each file name (while keeping the rest of the file name intact).
I want the file names to all remain different, but each end/begin with the same word or letter.