In this help doc
When you've got a problem, sending us screenshots help us to help you faster.
The ability to take a picture of your screen is built into your computer, it requires no additional software.
Below we show you how to:
Send us screenshots on a Mac
Press SHIFT + COMMAND (⌘) + 3 - this stores the screenshot as a file on your desktop. It will be called "Screen Shot DATE TIME.png"
As shown below, click on the paperclip in the messages app and find the screenshot on your desktop, click on it to upload. (You can also drag the image from your desktop into the messages app)
Send us screenshots on a PC
Press either PrtScn (Print Screen) or CTRL + PrtScn - this will copy your entire screen to memory.
As shown below, click on the messages app and press CTRL + V - this will paste your screenshot into the messages app.