The tester must constantly provide his boss with up-to-date information about his work. According to such reports, if they are made correctly, the boss draws a conclusion about the state of the project as a whole. Not only about the work of one tester or the entire testing team, but also about the work of the development team and the stage at which the project is. Also, such reports allow you to make an analysis for planning future releases, etc.
There are many examples when this work was not done or was done in an inappropriate way, from which the authorities had a feeling of uncertainty with all the ensuing consequences. I'll tell you the brightest one.
Once a tester was assigned to a new project. Since he did not know him well, he was given the task of sorting out and recording observations. Since it was something informal, we agreed that we would write in Google Doc. The person began to perform the task, after a week this task was checked, the tester was patted on the shoulder and he continued to work. Months passed, the authorities began to worry about why there were no tickets in the bugtracker and nothing was being done on the project. We began to figure it out, it turned out that the person continues to write in the same Google doc. Nobody said “Pot, don’t boil” and didn’t stop the tester, but he regularly continued to understand and record observations, while not making himself felt. There are bugs, and he found them, but he didn’t tell anyone, but only wrote them down in a file, which everyone forgot about a week later.
In fact, the expectation was that the person would continue to work formally, i.e. in the bugtracker, giving developers work to do with their tickets, but this did not happen. It seemed that the man did nothing, even though he worked. It is clear that the problem was not only on the part of the tester, but if he had made a regular report on his activities, misunderstandings could have been avoided.
Often, the lack of information creates a feeling of poor testing of the product, that this or that part of the functionality was not tested. To prevent this from happening, you need to draw up detailed reports, this is especially important on large projects.