Take a screenshot
To take a screenshot in Windows, "WINDOWS KEY - SHIFT - s" keyboard shortcut.
Taking Pictures with Phone
Taking a picture with a phone should be done as a last resort only. They are much harder to read than screenshots made by the Windows operating system or other software program.
Inserting full size in email
When you insert images into email, the default for many email programs is to resize the image. This makes it difficult to read the screenshot. For example, this is what it looks like in Gmail when I insert a screenshot. I added the red arrow to point out the ORIGINAL SIZE link. When I send screenshots using Gmail, I click ORIGINAL SIZE so that the original image in its full size is sent - not a scaled-down version. Other email programs will obviously present a different interface, but this "functionality" is common to many email programs.
Alternatively, you can attach the screenshot as a "generic" file instead of inserting the image into the text of the email. When you simply attach a file, the full image gets sent. It doesn't get resized or compressed.