Plain answers to the problems people meet most. Nothing here needs technical knowledge.
Each tool takes one kind of file, such as PDF or photos. Check the name of the file ends the way the tool says (for example .pdf). A file that was only renamed, like a Word file renamed to .pdf, will not work. Open the right tool for your file from the home page.
This site cannot open locked files and does not remove passwords. If the file is yours, open it in your normal PDF viewer with the password, print it to a new PDF ("Save as PDF"), and use that new file here.
The file may be damaged, or not finished downloading. Download it again. If it still fails, try the Repair PDF tool. A file that opens on your phone but not here is rare; please tell us through the Contact page.
Everything runs on your own device, so a very big file needs a lot of memory. Close other tabs, try on a computer instead of an old phone, or split the file into smaller parts first.
Some PDFs are only pictures of paper (scans). They have no real text, so tools that read text cannot work on them. We do not offer text reading from pictures (OCR). If you have the original Word or other file, make a new PDF from it.
Our tools write English and Hindi. Letters from other languages, and some rare symbols, cannot be drawn and are shown as a question mark. The tool tells you how many were replaced.
On a computer it is in the Downloads folder. On an Android phone, look in Files, then Downloads. On an iPhone, look in the Files app, then Downloads (Safari may also show a download arrow at the top of the screen). If nothing downloads, allow downloads for this site in your browser settings.
On the home page, press the / key to jump to the search box. On a tool page, copy a file in your file manager and press Ctrl+V (Cmd+V on a Mac) to add it, as long as you are not typing in a box. The star on each tool page saves it to Your favourites on the home page. The home page also shows the tools you used lately. All of this stays on your device and the Forget my settings button in the footer removes it.