I thought that buying a Windows-based tablet-whether the millennial denotation of 'tablet' or gramma's (or proctologist's :lol: )-would allow writing on anything, including Affinity's predecessor software. I realized only yesterday that PP (at least the version I had) did not have an interface that would allow handwritten annotations. Even some free image viewers like IrfanView do offer such things like making a screen capture and annotate on the captured image!
you just use one of those screen capture tools, open a textbox and type in with the good old plain keyboard the stuff you want to appear as an annotation.
And if you don't have or use a graphics tablet or Win tablet computer etc. Nah you don't need that for making annotations and screenshots, if you want to add handwriting a plain graphics tablet or a Windows notebook/tablet computer with build-in digitizer will do it.