Final answer:
Three key meta data tags in HTML are: meta charset, meta viewport, and meta description.
Step-by-step explanation:
- Meta charset: This tag specifies the character encoding for the HTML document. It helps browsers understand how the text should be displayed. For example, <meta charset="UTF-8"> sets the character encoding to UTF-8.
- Meta viewport: This tag sets the viewport's width and initial scale for responsive web design. It ensures that web pages are displayed correctly on different devices. For example, <meta name="viewport" content="width=device-width, initial-scale=1.0"> sets the viewport width to the device width.
- Meta description: This tag provides a brief description of the web page's content. It appears in search engine results and helps users understand what the page is about. For example, <meta name="description" content="Learn about HTML meta tags."> provides a description of the page's content.