Having tests run automatically instead of repeating them by hand, so they finish in minutes after each change or on a fixed schedule.
With automation, software carries out the steps a person used to perform: it opens pages, fills in fields, presses buttons and compares the result with what was expected. Traditionally this required a developer to write test scripts and maintain them whenever the interface changed. Today an AI agent can explore the site, write the cases and run them without scripts you write yourself.
Repeated manual testing is the first thing dropped when work gets busy, and automation makes checking a fixed habit that does not depend on anyone's mood. But it does not remove people: a machine is excellent at repeating known flows, while a human is better at judging taste and context and at finding what nobody thought of. Fanann's QA Engineer writes the cases, runs them in a real browser and repeats them on a schedule. Practical tip: automate first what you repeat every week and what hurts when it breaks, and leave free exploration to a person.