RTM (Requirement Traceability Matrix):- RTM is a documentation process to cover requirements with creation of test cases like a mapping between business requirements and test cases with functional requirements.
Please review below an example but it may be different as per your requirement. This is just an example to design it.
In below example:- 1. “User Registration is Business Requirement” with Functional Requirement of Email-Id and Mobile No.
2. “Login is Business Requirement” with Functional Requirement of Login With Email-Id and Login With Mobile No.
*keep practicing with different different examples for learning more*