The invisible thread is hard to see but it has a shine to it so you can "see" it while using it. Once you step back from it, though, it disappears. While you're quilting or appliqueing pieces down with it--it might be easier to look for the needle holes instead of the thread for some people.
You definitely have to play with tension on many machines to use the invisible thread. And much of it will whiplash so it needs a thread net or I put it in a coffee mug behind my machine. Some stick a piece of batting in the first thread loop to "tame" the thread. Winding it for bobbins is a pain, too. Slowly is the best advice I can offer for that or just using a silver embroidery thread instead of trying to use invisible in the bobbin.
The more I type about invisible thread, the more I'm liking the idea of putting a black blanket stitch around the critters--LOL!