What is hashing a message?

Could you please clarify what hashing a message entails? Is it a process that involves transforming a message into a fixed-length string of numbers and letters using a mathematical function, ensuring that the original message cannot be retrieved from the hash? Is it a security measure that helps to verify the integrity of the message and prevent tampering? How does it work, and what are some of the common hashing algorithms used in the cryptocurrency and finance industry?