If you have information that could put you at risk to share, do not send details in your first message. Email us saying only that you have something sensitive, and we will arrange an encrypted channel before you send anything.
Some practical advice regardless of who you talk to: do not use a work device or work network, do not use an employer-provided email account, and consider whether your access to the information could identify you on its own.
We do not disclose sources to third parties, and we do not retain identifying metadata longer than necessary to verify a story.