Here's how I do it.
I go into Word (MS Word)
Click "Insert" at the top of the window.
Click "Symbol" from the drop-down menu.
Then I hunt around until I find the symbol "√"
I highlight the symbol and click "OK."
Then I close the insert symbol window and go back to the document that now has the √. I highlight the symbol, press Ctrl-C. Then I go back to this site and press Ctrl-V.
If I'm writing something long, I'll do it all in Word and then copy the whole thing onto this site. That's done as follows:
Press Ctrl-A to highlight the whole Word document
Press Ctrl-C to copy it into the copy buffer.
Go to this window, and make sure your cursor's here, and press Ctrl-V.
But there's a better way that you can do here on this site. Use the exponent (1/2). It means exactly the same thing. and you don't have to bother bouncing around between applications. Thus "The square root of 4" might be written "√4" or "4^(1/2)," 4^(1/2) has mathematical advantages. It obeys the rules for exponents. [4^(1/2)]^2 = 4^[(1/2)(2)] = 4^1 = 4
If you're doing calculations, I think it's better to use the exponent 1/2. If you're expressing an answer that contains a square root, and if it's expedient, use √.