Quality assurance (QA) plays a crucial role in software development by ensuring that the software meets the specified requirements, functions correctly, and is reliable. QA involves activities such as creating test plans, developing test cases, executing tests, and reporting and tracking defects. QA engineers or testers focus on identifying bugs, issues, and inconsistencies in the software, performing functional and non-functional testing, and ensuring the overall quality of the product before it is deployed to users. QA helps in reducing the risk of software failures, improving user satisfaction, and maintaining the integrity of the software.