Just as any word processor has commands which modify the appearance and structure of text, so HTML has many such commands. Without such modifying tags, the text would be merely a string of ASCII characters with no breaks and with no more than one space between any two words. (ASCII, or American Standard Code for Information Interchange, is a standardized code in which characters are represented for computer storage and transmission by certain numbers.)

To see lists of special characters which can be inserted into HTML source code documents, go to Special HTML Characters, Special ALT Characters, and Special <Font Face="Symbol"> Characters. For special HTML characters, either the HTML code or the character code (if any) may be used. For special ALT characters, the Alt key on the keyboard must remain depressed while a sequence of numbers on the numeric section of the keyboard is typed. (The Num Lock key must be depressed to activate the numeric keys.) Many special HTML characters and special ALT characters are the same. Web browsers do not detect carriage returns (line breaks), tabs, extra spaces, nor other white space embedded in an HTML source code document. For instance, even if 10 spaces are present between two words in a source document: