my stepsis is always on some website call wattpad
I use my blog to share my unpublished writing and amazon for my published works. I like my blog a ton because I have free reign to write whatever I want. Also people can follow it and keep updated.
Amazon KDP is awesome for indie authors because five days you get free. Amazon actually markets on the free days. Just in three free days I've sold thousands of copies (not only because of amazon, I market myself too).
Belive it or not wattpad is a great site although you put the content of your book up there for free authors found sales in there book rose
I've been on wix.com, you can build websites and such, not sure if that's what you want but it's kinda fun to do anyway! Lol.
But yes, wattpad.com is a good one!! Some books on there even get published!
If you're writing fanfiction, try fanfiction.net.
Both wattpad.com & fanfiction.net are good ones, I think so at least..