HTML has special pattern, if I don't feel hesitation than tags are most important in the html. In coming lessons, tags are most interesting topic. In handwritten, there is no any limit where to start, where to end our sets of rules are applied and until page is full of ballpoint ink. In Microsoft Word there is a limit, we can not go beyond borders. We can not make any type style until customization ribbon help us. But in html everything is restricted and perfectly sequenced. Without ending and closing tags, you can not write any thing. But you can write un-parsed content. If you don't follow html rules then browser does not understand what you type. Actually HTML derived from xml. DOCTYPE declares the standard and version of html. Current version is 5. Doctype declares that html data is written in html 5 format. html tag comprising off all data.
doctype > <html> tag tag tag </html>
Next the title and the header. Title is basically additional item that is not in ms docs. Look at example.
doctype > <html> <head> <title></title> <head> tag.. </html>
The <head> tag contains other head elements such as <title>, <meta>, <link>, <style> <link> etc.
Next lesson will be on tags don't worry. Oh yeah you learn about fundamental tags of html. The body and then the footer.
The final look right here,
<!DOCTYPE html> <html> <head> <title>Hyprtext Markup Language</title> </head> <body>..</body> </html>