i) Attributes are special words used inside a tag to specify additional information to a tag. Attributes should be placed within the opening tag. Most of the tags support specialized attributes and there are also a few global elements that can be used with any tag.
ii) Global elements are common to all HTML elements; they can be used on all elements.

Comments are used to describe the page or provide some kind of indication of the status of the page. The tag < ! > is used to create comments. In HTML, the text what you type within this tag is considered as .comments and it is ignored by the browser. Comments never show up onscreen. Comments can be placed anywhere in HTML document. The general form of comments:
< ! comments >

Step 1: Open a Browser (Internet Explorer / Mozilla Firefox or any)
Step 2: Click File ⟶ Open File (or) Press Ctrl + 0
If menu bar is not visible in your browser refer in this picture.


Step 3: From the "Open" dialog box, browse the folder in which the HTML document is saved. Choose the File name and click "Open" button.

An HTML document contains the text of the page itself and HTML tags, which defined the structure and appearance of the document. It also contains hyperlinks to other pages or to include multimedia elements such as audio, video, animations etc. Entire HTML document is bounded within a pair of < html > and < /html > tags
HTML Document Structure:
< html >
< head >
< title > Title Name < /title >
< /head >
< body >
Body content
< /body >
< /html >