Webcomics are comics that are exclusively published online. They are becoming increasingly more popular. Making a webcomic is a quick way to get your work out there and to get others involved with your art.
Personally, I love print comics, but webcomics allow viewers to comment and engage with the work immediately, something that cannot be done with print comics. It really enriches the experience.
Great question! Pick a site where you feel a sense of community and get to posting! I chose comicfury.com as my main site, but there are many other places: Tumblr, Instagram, Deviantart.
Hope to see you on the internet!