VBA stands for Visual Basic for Applications. Basically, it's the
programming language that Word, Excel, etc. uses for writing macros.
The short answer is that Word does not have a built-in way to delete all
bookmarks in one fell swoop. So, you either do it from the Bookmark
dialog -- one at a time--or you write a macro to automate it... assuming you
don't want to lose any formatting or features.
Another choice would be to convert (Save As) the document into a format that
does not support bookmarks (such as Microsoft Works), and then convert it
back into Word format. Depending on how the document is set up, you would
lose some formatting.
Still another choice would be to copy the contents to the clipboard, paste
it into a blank Wordpad document, copy to the clipboard again, and then
paste into a new Word document.
There are a number of variations on this theme. You would have to experiment
to see which method preserves most of what you want preserved.