If you find your PDF report is too large to email, you will need to reduce the image quality of the photos used in it. To do this:
1) Tap on the Settings tab at the bottom of the screen.
2) Tap on "Reports".
3) Use the "Photo Quality" slider to reduce the quality of the photos in your report. Sliding this to the left will reduce the quality.
Note: For larger reports, only a small change in photo quality can make a substantial difference to the file size so experiment with this to find what works for your situation. As a rule of thumb, files larger than 20-25MB tend to have a chance of not emailing correctly.