For example, I use Xodo (https://www.xodo.com/app/#/) to add annotations to pdfs for studying etc. and when I add a Free Text element to a document, I size the box in a way so that the text does not overlap with original doc text or other Free Text elements (so I can actually use those notes later for study reference).
However, when I view the document outside of xodo (eg. google Preview in Drive or my local linux Document Viewer), there are two problems:

1. When viewed outside the app, words in the Free Text boxes may be split across multiple lines, so it may look like this:
   """
   This is so
   me free te
   xt
   """
   whereas in the xodo app itself they always reformat to respect the box boundaries but also keep words complete:
   """
   This is
   some
   free
   text
   """




2. Free Text in the app further does not represent what is seen in any other outside app in that the Free Text font size differs from what is shown in the app (which likely is a contributing factor to problem #1 above). Eg. A multi-line Free Text element created in the app will appear cut off in any other app because the text size has increased and the entire text cannot fit in the box boundaries.

I use the default 9pt text size and 0 thickness