Sending a screenshot can be done using the built-in programs on your computer:
On a PC, hold the Ctrl key and push the "Print Screen" or "PRT SC" button in the upper right-hand corner of your keyboard.
Then, open a program that handles pictures, like Word, and paste the image into the document. Save the document and attach it to an email that describes the problem you are having to email@example.com.
On a Mac, hold Shift + Command + 4 and you will see "crosshairs" - drag these around the item you want to take a screenshot of and this will be saved automatically on your desktop. Attach this to an email to firstname.lastname@example.org.