Whatever your reason for wanting to create a PDF from one or more Jpeg images, it's simple to do in Windows or using an online PDF converter. You don't need to install any software, either.
Convert JPG to PDF in Windows
If you have Windows 8.1 or later, you'll have a built-in PDF printer. If you have an earlier version, such as Windows 7, simply download and install Adobe Reader DC to get the same function.
We're using Windows 10 here, which includes Microsoft Print to PDF.
First, open Windows File Explorer (the shortcut is Windows+E).
Navigate to the Jpeg files you want. You can select multiple files by clicking and dragging a rectangle around them, or by holding Ctrl and clicking on each one you want. Obviously the files need to be in the same folder to begin with.
Now right-click on any of the selected files and choose Print.
This opens up Windows' built-in image printing wizard. Here you need to change the printer to Microsoft Print to PDF. If that's missing from the list, install Adobe Reader DC as we mentioned above.
You can use the options available in the wizard to put multiple images on each page of the PDF, and even change the page size from A4 to another size.
Once you've set all your options click Print.
You'll see the printing progress happening just as if the file was being printed normally but at the end a box will pop up asking where you want to save your PDF. You'll also need to enter a file name.
Click the Save button and your PDF will be created, ready to share with anyone you like.
Convert JPG to PDF online
If you prefer, you can use an online converter to combine multiple Jpeg files into one PDF. Or you can create a PDF from a single image.
There are many services which can do this for free: they all work in the same basic way. We're using JPG2PDF here.
Click the link above to go to the site and either drag and drop the Jpeg files or click the Upload Files button.
When your files are all uploaded, click the COMBINED button which should really say 'Download' as that's what it does.
You may have to edit the filename after it has downloaded as it defaults to jpg2pdf.pdf.