I assume by “Readdle” you mean PDF Expert 5, the current iOS version of Readdle’s document manager. I just created a PDF Expert 5 document, moved it to the desktop, and imported it to DEVONthink Pro Office. The document has a sticky notation, square, circle, line, highlights, cross-out, underscore, text, and stamps. Each of these is editable in DEVONthink Pro Office. I open the document in its own window, where the PDF annotation tools appear on the toolbar. I click the tool appropriate to the annotation type (sticky, text, etc.) and then click that annotation, which can then be edited.
Toolbar: