You can save any file format to PDF using Photoshop. Here is the step by step guide on save photoshop as PDF.
1. Open the desired file in Photoshop which one you want to save as PDF
2. Then go to “File” from Photoshop menu bar
3. Now select “Save as” from the drop down menu OR press Shift+Ctrl+S on keyboard
4. You can see a popup window now. Find the “format” option (Located just below the File name)
5. Select “Photoshop PDF” from drop down options.
6. Click on “Save” button
7. Now un-check “Preserve Photoshop Editing Capabilities” box. This will reduce the file size, so you can email the PDF file.
8. Now hit on “Save PDF”
9. If your PDF file is still too large then you can follow the previous 7 steps and then go to “Compression” just under “General” in the left side of save window.
10. In the option box just reduce the Image Quality from Maximum to High, Medium.