To set the default zoom for PDF documents, use File > Export as PDF… and select the “Initial View” Tab (see the screen shot below).
On this tab, you can set the desired magnification (zoom) for your PDF.
A Note on Default Zoom
It has been noted that default zoom settings perform differently depending on the operating system (Linux, Windows, Mac, etc) and the software used to open the PDF file.
For example, on a Mac the default application to open PDF files is Preview. As can be seen from the screenshot below, this overrides the default zoom settings.
It will depend on the application used as to whether the user-defined zoom settings will be applied. In Adobe Acrobat Viewer for Mac, if the page display preferences are set to ‘Automatic’, then it will use the creator’s zoom settings as the default. Changing this menu setting (see screen shot below) will override the document creator’s viewable settings.
Just another reminder that the creation of documents is not entirely dependent on a knowledge of the software we create it in, but also of the software that it will be viewed in.
If anyone has any experience in how to override an application’s default view settings for a PDF, please comment below, or contribute to the forum at http://oooforum.org.