Hi there, Alice, and welcome to Iwaku.
Did you by chance follow a kitty down here? ;D
Anyway, it's nice to meet you!
Since you're new, these are some places you'll want to check out: This is where you can sign up for the roleplays found in Modern, Scifi, Fantasy, and sometimes Mature. Generally, they will have you post a character sheet in their thread, a new sheet for each roleplay! You can also start signups for a roleplay of your own here.
This is where you can find jump in games, which typically have no sign up thread. You just start posting!
If you need any help or have any questions, please feel free to ask!