For general LaTeX questions, you'll often get a quick response by asking the LaTeX Users and Experts on a community forum:
and we recommend searching the LaTeX Wikibook (http://en.wikibooks.org/wiki/LaTeX/) for more information and examples.
If you have a question specifically about Overleaf and you can't find an in our online help, please get in touch via our contact form. Contacting us through this web email interface is the best way to get a response quickly. If your question is about a specific document you're working on, please include a link to the document to help us find any problems more quickly.