Most Word processors have the option to create a pdf from the document in their workspace. In Word, pdf is one of the save as options. In Word Perfect create a pdf is one of their options.
Im not familiar with LibreOffice but look carefully in their choices. Or copy file to Word or Word Perfect, etc.
An easy way to convert a .jpg or .png to .pdf is use the image insert feature of your word processor. Expand size as much as you dare (as limited by resolution). Then save as a pdf.
Another option would be a print-to-PDF “printer driver”. To other software it looks like another printer, but it writes whatever it’s “printing” to a PDF file. So suddenly every program on your computer can output to PDF.
In LibreOffice Writer, I have a red & white icon between Save and Print in the line below the menus. I click it and it saves it as a PDF.
Does that help you?
Yes, it does. Although it’s not red and white, it is the icon for pdf’s. I expected it to be in the Save drop-down menu, if it was going to be anywhere.