Scrolling is broken. Also for modals, it'd be nice to be able to click anywhere on the screen to close it (or pressing Esc) rather than just pressing "cancel".

Also for text, different fonts is a necessary requirement (and bolding, italics, underline, etc).

Also, it seems like I can't edit text boxes after creating them... I can't even tell if I've selected the text box (an outline would be nice).

Also the confirm modal for deleting a page is realllly annoying. You should just have it automatically delete the page and create an undo feature. (Basically store the original PDF, and store all the "actions" a user makes in an array, and then undo/redo the actions to the original pdf).

Also the arrow to close the page overview on the left side of the screen is very unintuitive. Why does the entire page shift to the left? The only reason I'd use that feature is to see my centered page more clearly. On this topic, a zoom feature is super important too.

Overall, the concept of a privacy-based PDF editor sounds really cool! Just note that for users to actually make a serious switch to this, you must at least match 1/4 of the quality of other PDF services like ilovepdf.com or smallpdf.com.

Good luck!