We don't seem to have a Public Key Infrastructure that makes digital (cryptographic) signatures useful for non-computer work. I think signing a document is a solemn act. So I don't want to just paste a .PNG of my signature, I want to actually sign it. I don't have a modern Linux device with a stylus. (Somewhere I have a ThinkPad x61 and a couple of Sharp Zaurus PDAs.) I do have an iPad and a ThinkPad C13 ChromeBook, both of which have styli. In each case it is a little intricate so I thought others might find my methods useful. Suggestions welcome. On the iPad: - I can plug in the ipad to a USB port of my desktop and instruct the iPad to act like an external disk drive - using Gnome Files, I can transfer the PDF to a directory on the iPad. - using the file browser on the iPad, I navigate to the PDF, long press on it, and select "Quick View". I don't want Adobe tools. - I can just write on the document with the stylus and save it. I usually save it with a different name, one that indicates that it is a signed document. - using Gnome Files, I copy the signed document from the iPad to my desktop. - Using Gnome Files, I "eject" the two removable filesystems that are the iPad's. I can then unplug the iPad On the Chromebook: - I have already installed the Linux subsystem. I start up the terminal in the Linux container. - I use scp to copy the PDF from the desktop to ChromeBook's Linux filesystem (my home directory) - I use the ChromeOS Files application to open the PDF file (the Linux container's filesystem is visible to Files). - I tap a snake-like symbol on the top of the screen (It seems to signify scribbling). - I write my signature - I save the result, with a distinct name, in the Linux Container filesystem - back in the terminal, I issue the scp with the arguments suitably adjusted (easy to type with bash's history mechanism). I find the ChromeBook a bit easier. Partly because WiFi is easier than wiring (I have only one lightening cable and it is usually hooked up to a charger). If I found an iOS SCP application that might even the platforms.