update value is what you’re probably looking for, but as for filtering the value to prevent ms word markup… more than likely there are some differences in what’s being submitted from what’s in the content editor. ACF may already be filtering part of the submission.
What you’ll need to do is echo out the value that you’re trying to filter, if you do echo $value; die; in your filter you can figure out what changes you need to make to your regular expressions.
My personal preference would be to tell the client to stop copying and pasting from word. It’s a bad habit. Trying to filter it is a never ending exercise in futility. 🙂
