How to use the attach files to pdf
- Choose the PDF you want to add files to. The page tells you how many pages it has and how many files are already attached.
- Choose the files to attach. Each file appears in a list where you can add a short description or remove it.
- Select Attach and save PDF to download a copy of the PDF that carries the files.
- Open the saved PDF in a viewer and look in its attachments panel to see the files.
What a PDF attachment is
A PDF can carry other files inside it. They are stored in an embedded files list in the document, each with a name, an optional description and a media type, and viewers show them in an attachments or paperclip panel. People use this to send a report together with the spreadsheet behind it, a drawing with its source, an invoice with its XML data, or a set of photos with a written summary, so everything travels as one file.
This tool adds those files without changing the pages of the PDF. Files that are already attached are kept. If two files share a name, the later one gets a number added, such as "data (2).csv", because each attachment name has to be unique. The media type is recorded from the extension, for example text/csv for .csv, and files with an unknown extension are stored as generic binary data. Descriptions are optional, up to 200 characters.
Checked by reading the result back
After saving, the tool reopens the new PDF and counts the attachments. In testing, a PDF with three attachments, including a text file, a small PNG and a second file with a repeated name, was read by an independent PDF library, pypdf, which found the same names and the same contents byte for byte, and a second round of attaching kept all earlier files. See the PDF attachment extractor to list or save attachments from any PDF.
Attached files are never opened, run or previewed here. Treat what you attach, and attachments you receive, as you would any file from outside: programs and documents with macros can be unsafe. Recipients with some older or simple viewers may not see attachments at all, so mention them in your message.
Limits and privacy
Everything happens in your browser and nothing is uploaded. The PDF can be up to 25 MB; you can attach up to 20 files of 25 MB each and 100 MB in all. Password-protected PDFs are not opened. Make the PDF smaller first with the merge PDF tool or edit its details with the PDF metadata editor if you need to. If the total is too big to email, the image compressor can shrink pictures before you attach them.
Assumptions and limits
- The PDF is not password protected and has at most the page count the shared PDF limits allow.
- The media type is chosen from the file extension and not from the file contents.
- Descriptions are plain text of up to 200 characters.
- Some PDF viewers do not show attachments, and some email systems strip or block certain attachment types.
Frequently asked questions
Does attaching files change the PDF pages?
No. The pages, text and images stay as they were. The new copy holds the same content plus the embedded files, and the original file you chose is not modified.
Will the recipient be able to see the files?
Most desktop PDF viewers show an attachments panel. Some phone apps, browser previews and simple viewers do not, so tell the recipient where to look or send the files separately as well.
Can I attach a program or a document with macros?
The tool does not stop you, but it is better not to. Many email and security systems block those files, and recipients are right to be careful with them. Attach data and documents instead.
What happens if the PDF already has attachments?
They are kept. The new files are added to the same list, and if a name clashes with an existing one, a number is added to the new name so nothing is overwritten.