An art trade is when to artists draw each other's character. For example I would send you some pictures of a character I'd like you to draw and you'd send me a link of one you'd like me to draw. Then we draw and post each other's characters. It can help people get to know each other, promote each other's art and to try and draw new things.
I would love to do that! Let's work out the details tomorrow, since I'm heading to bed right now. Give me a few options, or something specific, either way.
I guess it can be whatever. I usually either do a fullbody and transparent background or a fullbody with a simple background. Here are a few examples of art trade art I've done~ But these can be any level you'd like.