What is Unicode and which characters come under Unicode?

Unicode is an encoding standard in which you can send SMS in different non-English scripts and target a wider audience. It uses UTF 8 encoding of international standards and provides a unique number to each character. A 

Unicode is a 4 Byte character that covers all the non-English languages in the world.
It is compatible with all the browsers, devices, search engines, operating systems, and other parts of the internet ensuring a seamless multi-platform system to convey text messages in different international languages.

A typical SMS credit consists of 70 Unicode characters unlike that of GSM-7 (English text characters) whose 160 characters make an SMS credit.  

Below are some of the characters which are treated as Unicode, along with this emojis or emoticons are also considered Unicode.

Note: All junk and hidden characters act as Unicode.