Static annotations are burned into the page when the PDF document is created. Most software (including PDFClerk Pro) cannot alter this content, or only offers limited editing capability. (Note however that these annotations always remain editable in the PDFClerk Pro file.)
To edit static annotations activate the Edit Static Annotations work mode [command-3]. When the mode is active all static annotations are marked with a red rectangle along their border. Selected annotations will also show manipulation handles, which can be used for resizing and/or rotating the annotations directly on the page.
Static annotation properties can be edited in the Metrics and the Appearance Inspector. As with other annotations you can either tell PDFClerk Pro you want a new static annotation and then drag a selection to size an annotation, or click on a page for an annotation to appear, or you can select some text and then select one of the static annotation shapes from the menu. This will create an annotation whose bounds neatly enclose the selected text.