Does TM need to be registered?

Assuming you mean "does it need to be registered to be enforceable", the answer is "not necessarily."

In the United States, for example, the first use of a distinctive mark in association with goods or services may create statutory and common-law priority rights that can be used to prevent others from later using a mark that is "confusingly similar."

However, registration (state or federal, or both) provides additional protection and makes the enforcement of a valuable brand that much easier.