Looking for Zoella's Snapchat?
I'm sorry to break this to you, but she doesn't actually use Snapchat that much. She had an account, but got bored of it pretty quickly, because she didn't know anyone cool on there.
Besides, she has been pretty busy trying to keep up to date with her other social media profiles:
Where you can find Zoella on social media (other than Snapchat)
Twitter - https://twitter.com/ZozeeBo
Tumblr - http://zoella.tumblr.com/
So forget about trying to Snapchat Zoella, and get in touch with her on one of her other social profiles instead.
She is cute and lovely to all her fans, so there's a good chance she will reply to you if you tweet her for example (especially if you make the effort to tweet something funny or cool).