Avoid omitting <head> tag
Generally, the <head> element contains metadata like document title, styles, links, scripts, and other similar information. The omission of the <head> element isn't the end of the world for the HTML page. Browsers will simply add this information before <body> and call it a day. However, we'd recommend keeping the <head> element to avoid confusion among developers and provide consistency.
From Lesson
HTML Dos and Don'ts