Does Signal read your messages?
No — Signal cannot read your message contents, because chats are end-to-end encrypted by default; only you and the recipient hold the keys. What it can still see is metadata: Sealed sender hides the sender from Signal's servers; private contact discovery and encrypted profiles/groups minimize what the server can see, but a central server still routes all traffic.
Even when contents are encrypted, the service usually still sees who you talk to and when. Signal's identifier model: Phone number is required to register; an optional username lets you be contacted without sharing the number. RVNT removes the server from the equation entirely — peer-to-peer, sealed sender, Tor by default: RVNT vs Signal.