The namespace of String.Copy() method is System. Similarly the assembly of String.Copy() method is System.Runtime.dll. Copy() is public built-in method which mean it can be accessible anywhere in code with string class. String.Copy() method is used to create a new instance of String with the same value as a specified String.
In below example, we have string with named s1 which have value Grasp. string s2 = string.Copy(s1); here Copy method will create copy of existing string s1 and store it in new string s2.