If you open the PDF file, which was annotated in PDF Expert, using a third-party app (e.g. some cloud storage application or email client which use simple PDF viewer) and do not see your edits, this means that the third-party app you use might not support all the advanced features supported by PDF Expert and this app does not display edits. For example, its PDF viewer does not display annotations or PDF form's data you filled in while the annotations and PDF form's data remain in the file.
There are two ways to cope with the issue:
Flattening is a process of applying all annotations and form data to a PDF.
Flattened PDF files are used:
If that does not help, please drop Support Team a line and we will get back to you as soon as possible.