How is a web application tested?

Question

Software testing

Hello. Explain how web applications are tested in simple terms. for example, there is a small online store that works on the rest with its own api. express react mongodb.
What is tested and how?
as I imagine: they
check forms,
check if all links work,
check if errors are shown, warnings for the user in case of unusual behavior,
pages like 404.
what else??
I look about testing, it seems to me there is more abstruse terminology than real work.
write a rough plan for the points of what and how to test.

Answer 1

What and how is tested ???.... in simple language.... I look about testing, it seems to me there is more abstruse terminology than real work

No, it's just that simple. Roughly speaking, there are three levels:
There are also spot tests that are not always done and they somehow exist on their own. For example, checking the performance or security of the system. On small projects, this is almost never done.

Answer 2

There is TK.
Check the compliance of the work with this TOR.
Check that after the updates the old functionality is not broken.
Verify that integration with other products is implemented correctly.
By hand or automated.