Meta Data information not visible on the frontend user but it’s used for search engine result display.

Please check the screenshot for your reference.

For Meta Title
Meta Title should be less than 60 character length because after 60 character Meta title showing (…) in the search engine. You can see in the screenshot (…) showing in the meta title.

For Meta Description
Meta Description should be less than 155 character length because after 155 character Meta Description showing (…) in the search engine.