What is the purpose of strong and em tags in html?

[RichaGhosal]

What is the purpose of using strong and em tags in HTML? Throughout my career, I believed they helped blind people better understand the websites I developed. However, while mentoring others, I tested how screen readers interpret these tags and discovered that neither the built-in Windows screen reader nor NVDA made any intonation changes on strong, em, b, or i tags. This has made me curious about the true significance of omeglz online2yu using them. Can you please explain their purpose?