Solution 1 of 2

Open Firefox

1. Hit the ALT keyboard button to display the menu at the top

2. Select FILE then PAGE SETUP

3. Change to 100%, check Shrink To Fit Page Width (see below)

4. Click OK

Solution 2 of 2

1. Open the email.

2. Print via the printer icon at the upper right.

3. The email will open in a printable format