Well, could I? I could rave about how great I am. I could provide my history and education. I could provide links to, well just about anything.
Is this possible?
There’s nothing stopping you from creating it, but unless you are actually a notable person it would get deleted in about 5 seconds.
Edited to add: actually you can definitely do all that stuff on Wikipedia, it would just have to be on your user page and not on an actual encyclopedia article (again, this is assuming you don’t meet Wikipedia’s standards for notability…nothing personal.)
A couple of other relevant Wikipedia policy pages that I haven’t completely read through but should address your question(s):
It is possible to do so, but policy generally holds that the content should not be added by the subject themselves in order to preserve objectivity.
Still this does not stop many (barely) notable people from doing so by having a friend post it for them.
Also the information needs to be factual and suppored by references or it is likely to be edited away.