if you've been sent this carrd link, it means that someone wants to explain to you what them being a system is.
this carrd is made to explain systems in both medical and non-medical standpoints. this carrd is by no means sysmedicalist, or even pro-endo. this just has information regarding these things.

a system is, in both medical and non-medical standpoints, a term to describe people who have alters or other entities in their head besides themself. this is most often caused by childhood trauma according to the dsm v, notably being traumagenic, disordered systems, however some systems claim that they do not have trauma, and formed spontaneously, or out of willpower, notably being endogenic systems.

most traumagenic systems are disordered, meaning that being a system is a "nuisance" in their lives, for lack of a better term as of writing this. they usually have issues on a day-to-day basis due to being a system.most endogenic systems are not disordered, meaning that they do not feel it is a bad thing for them to be a system, and have no issues functioning daily.however, there is the case where traumagenic systems may not feel they are disordered, and vice versa. this puts a grey area on whether certain systems are valid, so i will not speak on it further, as i (the creator of this carrd) do not have any interest in syscourse.

syscourse is a term in the wonderful online world of systems that is basically the first debate: are endogenic systems valid?a lot of things that come from this discourse are not inherently good on either side, but yet the question still stands. usually, it is on endogenic systems invading traumagenic spaces, who is allowed to use what discord bot for proxying, etc. it is a mess and i do not want anything to do with it.

proxying is pretty much a discord exclusive thing, where one uses a bot to communicate through webhooks as the desired alter or person. this can also be used for roleplay, and many system-based bots have yet another syscourse debate on whether roleplayers should be allowed to use it or not.
the following image is an example of proxying with pluralkit, a notable example.