Saving output from PDFs merged using Automator
When working with Automator workflows, it’s always good to check hat an action takes as its input and what it returns as output. Usually, this is indicated in the action’s description (accessible either in the bottom left below the action browser, or by clicking on “description” in the action’s bottom row. The actual output when running the action can also be checked (by clicking “result” in the bottom row of the action).

In your case, checking will show the “Combine PDF Pages” returns a PDF Document file. This file can be processed by any Automator action that can handle files in general (for file operations) or PDF files (for further editing). A look in the “Finder” category of Automator will show you likely candidates:


Move Finder Items will move the file to a target folder of your choice. You can set a fixed one, or tick “Show this action when running the workflow” in “options” (bottom row again) to select each time you run the workflow. This action, again, returns a PDF Document, which
Rename Finder Items will rename a file. As the action returns a PDF Document, you can daisy chain rename actions with different settings, for instance to give it a selectable base name (choose “rename single item” and tick the show option), add a date stamp (add another actions et to append the date) and a time stamp (same procedure, now with the time).