Hi, if you can't ask ask your professor for a pdf version of the the LOR, I recommend scanning your LOR or taking a picture of it and converting it to a PDF.
If you have an iPhone, there's an option to do it through your "notes" app.
Go to "notes," make a new note. Click the icon of the camera and it'll say "scan documents." Click save then the top right corner should have three dots in a circle. Click that. You can send that image to yourself. If it needs to be in pdf form, I recommend using this site to convert it to a pdf - https://smallpdf.com/jpg-to-pdf