Difference between String and StringBuffer

Answer 1

You really need to write better questions to make it easier for people to answer. Please read this for your next question.
https://www.sololearn.com/Discuss/333866/?ref=app

Assuming your talking about Java. This is a great description
https://stackoverflow.com/questions/2971315/string-stringbuffer-and-stringbuilder

Answer 2

https://www.javatpoint.com/difference-between-string-and-stringbuffer