You can quickly combine multiple files (such as JPEG photos) into a PDF right from your desktop or a Finder window.
In the Finder (Desktop) on your Mac. Select the files you want to combine into a PDF. Note: Click the first file, then hold down command while clicking the others. Note: The files appear in the PDF in the same order that you select them. Control-click the selected files, then choose Quick Actions > Create PDF. The file is created automatically with a name similar to the first file you selected. You can open this file and rearrange, rotate, or erase individual pages.