what is difference between String and StringBuilder

String :

• String is the Immutable.
• Data value may not be changed and variable value may be changed.
• We can use the memory  size is cannot be increased.
• Namespace of the String is System.Text.

StringBuilder :

• StringBuilder is mutable.
• Data value may be changed and also variable value may be changed.
• Which we can used for memory size is can be increased like append, insert and etc......
• StringBuilder is faster than Strings.
• NameSpace of the StringBuilder is System.Text.StringBuilder.