In this category we find a variety of websites, a bunch of facebook-groups and some chat-servers.
The most important website to know about is "Blender artists".
This is probably the main hub for blender users on the whole internet. The site offers a forum with an array of subforums for different purposes. There is subforums for diferent kinds of discusions, for support and tutorials to mention a few of them. You can also ask for someone to critique a spesific project you are working on, or one that is finsihed.
Blender stack exchange.
Stack exchange is a platform where groups can create their own question based forum . The "Blender stack exchange" is one such group. You can ask questions about everything blender.
The blender community on reddit has alot of users, you can ask for help or just upload something you want to show other artists.
The number of facebook groups is many but these are the most important ones. You can do a search to find other groups than mentioned in this thread.
By far the largest blender group on facebook. Probably one of the most important if you are looking for advice or help.
Blender for absolute beginners.
This is a group focusing on the beginner stage of learning blender. it is an active community with experienced members as well as beginners.
Blender help for absolute beginners.
Originally started by users that for different reasons didnt like the other beginner group, this group is i good alternative to the much larger group.
This is the group for the community on the "Blender artists" web site, on facebook.
Blender 3D artists.
Another group of a certain size!
These are the sites i think to be the most important ones. If you know another site that should be on this list, please reply to the thread.
Most chat server groups use discord. Amongst them, "Blender" is the largest and most active. You might remember "Blender" from the facebook groups, and this is the discord version of that group. But wait, there is another discord group with the same name! But dont get confused, they are two seperate groups with the same name.
There is also the "Blender NPR" (non photo realistic) which focuses on renders that are not photo realistic.
There are probably more of them, but these are the ones i know about.
Places to find text documents
I used to have links to many of them, but after an incident with my hardrive i lost most of them. There is one very important one though, the blender documentation. I am not providing the link, you can google it or find it under the help menu in blender.
The documentation will not teach you how to be an artists, but you can learn all the technical stuf and how to use blender. I strongly recommend that you try it out once you get going. It is hard reading though, i recommend you get some experience using blender first.