PDF Studio

Yes. It takes a little more than a Latin one, which is why the note appears when you type such a letter. PDF's fourteen built-in fonts use an encoding called WinAnsi — Latin-1 plus a handful of typographic extras — with no Cyrillic at all, and of the Azerbaijani alphabet only ö, ü and ç: not ə, not ş, not ğ, and not even ı, which appears in almost every word. Writing those means embedding a real font in the file, so the page fetches one the first time it is needed: a 46 KB subset of Noto Sans, cut to Latin, Azerbaijani and Cyrillic. Only the letters actually used are written into each document, and a watermark in plain Latin still uses the built-in font and downloads nothing.

Yes — digits, spaces, slashes and dashes are all in the built-in encoding, so numbering works whatever language the document itself is in. It is only free text that runs into the font limit.

No, it adds to it. Scanned pages very often arrive with a rotation already set, and replacing it turns a correction into a new error — the page ends up square with the scanner instead of square with the reader. A page turned twice by 90° in this tool comes out 180° from where it started, whatever it started at.

It leaves the list, and the file it came from stays open, so undo brings it back immediately. Nothing is written until you press Build, and the originals on your device are never modified at all — the tool only ever reads them.

Thumbnails are drawn only as pages scroll into view, so opening a long document is quick regardless of its length. The limit you will meet is memory: every page you export is copied into the new document, and a few hundred megabytes of scans will make a browser struggle. Splitting into several files rather than one helps.

Yes. Double-click a page to open it, then click any line: the studio covers that line and hands you its own words to retype, at the same place and size. You can also drop in new text, white out a patch, and place a signature or logo. It works on any PDF that has real text in it — a scanned page has none, so there you white out and type instead.

No, and this matters. The old words are still in the file underneath the white box: anyone can select them, or pull them out with a text extractor. It is exactly what a sheet of correction tape does — it hides, it does not delete. Do not use it to hide a password, an address, or anything else that must truly be gone.

No. The files are read in the page, the new document is assembled in the browser, and the result is handed straight to the download. Closing the tab loses the arrangement — there is nothing on a server to come back to.