If you create a new image PDF file through scanning, just do as below:

 1. Choose Scan on the sidebar and click  , there you can take photos or import photos from Gallery;

 2. Then click Finish, here you can adjust them, and click Use;

 3. Then you can change the filters and edit the photos;

4. After that, click  and choose Store as PDF;

 5. Or you can click Done, then tap  Export as PDF.