There are so many drawing software that cater to the needs of all sorts of people from the hobbyists to the professionals. Some programs are much more powerful and feature rich compared to others. The drawing programs that are geared towards professionals often provide team contribution over a network in order to speed up collaboration of many different artists on the same picture. So what happens is that one artist creates the outline, another fills in the color or shades, and after many revisions back and forth a masterpiece is finalized.
Drawpile offers all the drawing tools you would find in a standard layer based image editor brushes of many different types and colors, erasers, shapes, filling tools and more. But the real power of Drawpile is in its networked collaboration approach. For this, you can either host a networked session yourself or you can join one of the sessions already started by others. These options are available from under the Session menu in the menubar.
If you want to join sessions started by others, then you will find a list of all the sessions available. Some of these are password protected and others are not clean both of which you can filter out from the options given in the list. Joining a session takes some time and after a session has been joined you can contribute to the drawing and take part in the text based chat.
If you and your friends want to host a session of your own, then one of you should start a session and password protect it so that nobody outside your group can join. Drawpile can be hours of fun for digital artists as it packs all the tools you will need to create and contribute to digital artwork.
You can download Drawpile from https://drawpile.net/.