Software testing is a basic activity that allows for detecting and resolving technical issues in source code, as well as assessing the overall product usability, performance, security, and compatibility.
QA aims at verifying that all the stages of a development life cycle align with quality criteria. A QA team focuses on improving the software engineering process to achieve the highest efficiency and deliver solutions that meet quality standards.
Software testing enables to timely detect and fix bugs, while the main objective of QA is to prevent any bottlenecks.