Manual testing is the process in which QA analysts execute tests one-by-one in an individual manner. The purpose of manual testing is to catch bugs and feature issues before a software application goes live. Manual testing is very hands-on. It requires analysts and QA engineers to be highly involved in everything from test case creation to actual test execution. 

Automation testing helps testers execute more test cases and improve test coverage. When comparing manual vs. automation testing, manual takes longer. Automated testing is more efficient. Automation testing involves testers writing test scripts that automate test execution. (A test script is a set of instructions to be performed on target platforms to validate a feature or expected outcome.).