Frequently Asked Questions

Yes. ModiPDF is free and does not require an account. The site shows advertising to cover its running costs.

No. Your files are read and processed inside your browser tab using the open-source libraries PDF.js and pdf-lib, and the exported PDF is created on your device. The website loads its own code, a PDF.js worker script and advertising over the network, but those requests do not contain your documents.

Related guide: Keeping sensitive documents private

You can open PDF files and JPG or PNG images. Each image becomes one page in your document. Other image formats, such as HEIC or WebP, may not be included in the exported PDF, so convert them to JPG or PNG first.

Related guide: Converting images to PDF

Open the first PDF, then click the + button at the top of the Pages panel to add more files. Drag the page thumbnails into the order you want and click Export. All pages are saved into one new PDF.

Related guide: How to merge PDF files

Drag thumbnails in the Pages panel to reorder them. Hover over a thumbnail to reveal the rotate and delete icons. To act on several pages at once, hold Ctrl (Cmd on a Mac) while clicking thumbnails, then use the Rotate or Delete buttons in the right-hand panel.

Related guide: Reordering, deleting and rotating pages

Yes. Open the PDF, delete the pages you do not need, and export. The new file contains only the remaining pages, and your original file is not changed.

Yes. The toolbar has Text, Image, Shape and Sign tools. Text and rectangles are placed where you click, images are chosen from your device, and the Sign tool lets you draw a signature with your mouse or trackpad. Use the Properties panel to adjust size, position and colour.

Related guide: Adding text, images and a signature

A drawn signature is an image of your handwriting, similar to signing paper and scanning it. It is not a certificate-based digital signature. Whether it is accepted depends on the recipient and on local law, so check with them if you are unsure.

No. ModiPDF does not have a redaction tool. Drawing a filled rectangle over text hides it visually, but the text usually remains in the file and can be copied. Delete the whole page if possible, or use dedicated redaction software.

No, ModiPDF does not compress files. The exported PDF is roughly the size of the pages and images you put into it. If you need a smaller file, reduce the resolution of large photos before adding them.

ModiPDF does not change the original text of a page. You can add new text, images and shapes on top of a page, and reorganise, rotate or remove pages.

Common causes are characters the standard export font cannot represent (such as emoji or non-Latin scripts in added text), images in formats other than JPG or PNG, and password-protected PDFs. Also note that added text, images, shapes and signatures are currently saved onto pages that come from PDF files; to annotate a photo, convert it to a PDF first and reopen that PDF.

There is no fixed limit set by ModiPDF. Because processing happens on your device, the practical limit depends on your browser and available memory. Very large documents may take longer to load and export, especially on phones and older computers.

Your loaded files and edits are cleared, because nothing is stored on a server. Export your document before closing the tab. Within a session, Undo and Redo in the header reverse page changes such as reordering, rotating and deleting.

The editor needs a connection to load the page, but once it has loaded, the editing and export steps themselves run on your device. The interface is designed mainly for desktop browsers; it may work on tablets and phones, but drawing signatures and precise placement are easier with a mouse or trackpad.