#pragma region lets you specify a block of code that you can expand or collapse when using the outlining feature of the Visual Studio Code Editor.

#pragma region name
#pragma endregion comment

comment
(Optional) A comment to display in the code editor.

name
(Optional) The name of the region. This name displays in the code editor.

#pragma endregion marks the end of a #pragma region block.

A #region block must be terminated by a #pragma endregion directive.

// pragma_directives_region.cpp
#pragma region Region_1
void Test() {}
void Test2() {}
void Test3() {}
#pragma endregion Region_1

int main() {}

Pragma directives and the __pragma keyword