There are some words reserved in HTML which we cannot use directly. If you use Less Than (<) or Greater Than (>) then the browser may get some error in it and some words are not present on the keyboard like copyright sign (©). There are some such type of venom characters, and to display these venom characters, there are poison codes in the HTML. Hence the HTML units provide a series of letters. For these words we use the letter organizations of HTML.
Non-breaking space:-
The above sign is of non-breaking space, it does not allow the line to break, without breaking the line, it gives space between the two words in that line.
Example:-
<body>
<h1>This is h1 heading.</h1>
</body>
In the above example, we have inserted this code between h1 and heading which gives a space in it without breaking the line, which can be output as follows.
Output:-

Use an Entity:-
In this, let us see how we can use these codes of HTML. Each unit starts with ampersand (&) and ends with semicolon (;). Entity names are case sensitive. Below are some examples.
Result Description Entity Name Entity Number
non-breaking space  
& ampersand & &
< less than < <
> greater than > >
" double quotation mark " "
' apostrophe ' '
¢ cent ¢ ¢
£ pound £ £
¥ yen ¥ ¥
€ euro € €
© copyright © ©
® registered trademark ® ®
Diacritical Marks:-
Some such syllable letters are found in HTML which add glyph below or above the letter.
Some Examples:-
Mark Character Construct Result
̀ a à à
́ a á á
̂ a â â
̃ a ã ã
̀ O Ò Ò
́ O Ó Ó
̂ O Ô Ô
̃ O Õ Õ