Deploy (Publish) Web Project using in Visual Studio

I just recently discovered that there are differences in the web.config file of a development environment to that of a production environment. I was reading articles about this and did not fully understand it.

https://learn.microsoft.com/en-us/previous-versions/dd465326(v=vs.100)?redirectedfrom=MSDN

https://learn.microsoft.com/en-us/aspnet/web-forms/overview/older-versions-getting-started/deploying-web-site-projects/common-configuration-differences-between-development-and-production-cs

I thought that when using the "Publish" option in "Build" menu, it will automatically do the necessary changes in the web.config (like changing the compilation debug="true"), apart from the connection string, mail settings and SessionState.

In one of the articles, I read a line where it is stated that Visual Studio can automatically do the necessary changes when we use the publish tool from VS, please, is that true?

I will please like to get a clarity on this and also, if possible, a brief step-by-step direction on the things that needs to be done in my own web.config file?

Thank you.

Here is a sample of my ASP.NET Web Application web.config

<configuration>
  <connectionStrings>
    <add name="ConString" connectionString="MyConnectionString" />
  </connectionStrings>
  <appSettings>
    <add key="ValidationSettings:UnobtrusiveValidationMode" value="None" />
  </appSettings>
  <system.web>
    <sessionState timeout="120"></sessionState>
    <authentication mode="Forms">
      <forms name="login" timeout="120" cookieless="UseCookies" loginUrl="Login.aspx" slidingExpiration="true" />
    </authentication>
    <authorization>
      <deny users="?"/>
    </authorization>
    <compilation debug="true" targetFramework="4.7.2" />
    <httpRuntime targetFramework="4.7.2" maxRequestLength="3145728" />
    <customErrors mode="Off" />
  <pages enableEventValidation="false">
      <controls>
        <add tagPrefix="ajaxToolkit" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" />
      </controls>
    </pages>
  </system.web>
  <system.net>
    <mailSettings>
      <smtp deliveryMethod="Network" from="emailaddress@mymail.com">
        <network host="smtp.secureserver.net" port="20" enableSsl="false" userName="emailaddress@mymail.com" password="password" defaultCredentials="false" />
      </smtp>
    </mailSettings>
  </system.net>
  <system.web.extensions>
    <scripting>
      <webServices>
        <jsonSerialization maxJsonLength="819200000">
        </jsonSerialization>
      </webServices>
    </scripting>
  </system.web.extensions>
  <location path="Signup.aspx">
    <system.web>
      <authorization>
        <allow users="*" />
      </authorization>
    </system.web>
  </location>
  <location path="Default.aspx">
    <system.web>
      <authorization>
        <allow users="*" />
      </authorization>
    </system.web>
  </location>
  <system.codedom>
    <compilers>
      <compiler extension=".cs" language="c#;cs;csharp" warningLevel="4" compilerOptions="/langversion:7.3 /nowarn:1659;1699;1701;612;618" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=3.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
      <compiler extension=".vb" language="vb;vbs;visualbasic;vbscript" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008,40000,40008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=3.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
    </compilers>
  </system.codedom>
</configuration>