It’s not hard to find images to use online – just use an image search. This works well, but it’s worth noting that doing so isn’t necessarily legal. Most of the images you can find this way are owned by their original creators. This likely doesn’t matter if you’re only using something for private use, or even a school assignment, but if you intend to publish a work you need to make sure all rights are cleared.
I'm seriously angry that Clipart is gone. Why? Because many of those cheesy images were available as Vector Graphics. So, I could quickly insert a crappy clipart into my powerpoints, ungroup the elements of it and delete all but what I wanted. I used it and it worked awesome for me multiple times. I wrote clipart off for years and only started doing this in the past 2 years...I wish I had known earlier.
If you mean your own artwork, then you'd take a picture of it, upload it to your computer (make sure you know where you're saving it), then select Insert > Picture in Word, browse in the location where you saved the photo, click the picture, and insert. If you mean an image from the internet or something, you can just save it to your computer and basically follow the rest of the steps above.
As an artist I resent some people's assumption that original art from my abilities and imagination, which I have sacrificed a lot to develop, should somehow default to public property. If we require artists to participate in a money economy their art belongs to them. Copying images and not following the copyright owners permissions to the letter is stealing, outright. And deep pockets like Disney has taught individuals that the hard way.