Hide website background management

Recently, I searched some search materials and thought about security based on some actual search experience:
Example:
Use GOOGLE search commands
Intitle: Management
Intitle: Background
Intext: admin
For some simple search commands, you will find the management backend of many websites ~~~
For example, if I use the hacker's light and the hacker's cracking tool, James [forgot the tool] ~~~
With dictionary tools, even if it is difficult to crack, but hundreds of thousands of websites, it is estimated that a few will be able to crash if you are lucky !!!
This is just a security risk. How can this problem be solved?
Exposing the background of your website is not so reassuring. Here is a tip:
Most of the Search Engine's [Search Engine policy.pdf program strictly complies with the robots.txt standard for execution and capturing. Any files that the robots.txt Standard considers to be unsuitable for capturing are neither included in the documents nor included in the search engine database. [Want to know