How do I toggle header/cpp file via keyboard shortcut in Visual Studio Code?

You can use the extension ms-vscode.cpptools to Switch Header/Source.

• If you’re on Mac, then the shortcut is ⌥ O (option + O key).
• On Windows, the shortcut is Alt+O.

Old answer:

There are currently a couple of extensions that support header/source file toggling:

• bbenoist.togglehs
• ryzngard.vscode-header-source

You can find more by searching the words “switch toggle header source” in the extensions tab in vscode.