To support the rendering of annotations on printed PDFs in Android and PDFs viewed by iOS email, you can use the method FlatAnnots().

Note: A preimum license is required for this method.

Example:

m_doc.GetPage0().ObjsStart();
m_doc.GetPage0().FlatAnnots();
m_doc.Save();

From Javadoc:

/**
 * remove all annotations and display it as normal content on page.
 * this method require premium license.
 * @return true or false
 */
public boolean FlatAnnots(){}