The automation of the tests consists in the use of software tools to control and configure the conditions prior to the tests, to execute the tests and to compare the actual results against the expected results.

How does the automation of tests help us, and what are their benefits?
The automation of the tests will allow us to have a greater coverage

Think for example that changes have been requested to 5% of the functionalities of the system, when this 5% of the functionalities are updated, the testers need to test that modified 5% and we still need to execute 100% of the remaining tests for ensure that there were no new errors introduced and that the existing functionalities continue to work as expected and have not been modified by mistake.
We can see that this effort grows as the system grows and can become unsustainable or too expensive.

Automated tests allow you to run regression suites that otherwise would be very difficult to achieve.

Test cases can be accumulated throughout the life of the application so that
both existing and new features can always be tested

Reduce testing times

Automation helps reduce time by allowing, once the tests are created, their execution can occur 24×7 if necessary, without the testers present and without any additional cost.

It allows cross-browser testing (ie testing through browsers) with the same lines of code, which would take us much longer manually to have to test the same test cases in various combinations of operating systems, browsers and cellphones.

By reducing time, this brings us to the reduction of software costs in the long term, at this point it is important to bear in mind that the implementation of automated tests requires a great effort mainly at the beginning.

Automation provides a great consistency: test cases are always executed in the same way, following the same steps.