Digital Representation
Because the © symbol has long been unavailable on typewriters and ASCII-based computer systems, it has been common to approximate this symbol with the characters (C).
The character is mapped in Unicode as U+00A9 © copyright sign (HTML: © ©). Unicode also has U+24B8 Ⓒ circled latin capital letter c (HTML: Ⓒ) and U+24D2 ⓒ circled latin small letter c (HTML: ⓒ). They are sometimes used as a substitute copyright symbol where the actual copyright symbol is not available in the font or in the character set, for example, in some Korean code pages.
On Windows it may be entered by holding the Alt key while typing the numbers 0169 on the numeric keypad. It can be entered on a Mac by holding the Option key and then pressing the "g" key.
Read more about this topic: Copyright Symbol