Software life cycle is a step by step process/ sequential steps that used is used test the application. It includes the testing process of a software application from the beginning to the end around various aspects such as functionality, behavior, performance, security and so on..
STLC runs parallel to Software development life cycle [SDLC]. It is used to ensure that the software is of high quality, meets the customer requirement and should be reliable.
The stages of STLC include
System study
Write test plan
Write test cases
Prepare Traceability Matrix
Testcase Execution
Defect tracking
Prepare execution report
Release retrospective meeting