In your Mac, launch any application. For example, if you are using Microsoft Word, open the document you want to save as a PDF.
Error in saving as Adobe PDF | macOS Mojave 10.14
Problem: Error in saving as Adobe PDF
In macOS Mojave (v10.14), when you try to print a document to PDF, using the System Print Dialog > Save As Adobe PDF, the following error message is displayed: "This workflow contains the action Save As Adobe PDF, which is provided by a third party. Third party actions must be explicitly enabled."
Select File > Print, or press Cmd + P.
In the PDF drop-down list, select Save As Adobe PDF.
You get an error: "This workflow contains the action Save As Adobe PDF, which is provided by a third party. Third party actions must be explicitly enabled."
To resolve the problem, follow the steps below:
In Mac, launch Automator.
Go to Automator > Third Party Automator Actions.
The Third Party Automator Actions dialog is displayed. Select the Enable Automator Actions From Third parties option
and click OK.
You can now print your documents to Adobe PDF.