Code Templates
Type the first letters from the template name and trigger Content Assist. Code templates are preceded by the “Template” keyword.
Custom Templates
VS Code allows to create a custom code template, using the Code Snippets feature. Use the Snippets: Configure User Snippets command and choose a language for which the snippets should appear. Alternatively, you can choose to configure snippets at a workspace or global level.
For a comprehensive reference regarding custom snippets structure see the Code Snippets - Create your own snippets chapter in the official VS Code documentation.
To insert a custom code snippet, you can either use the content assist or the Snippets: Insert Snippet command.