Your variable names are confusing and make your code hard to understand and debug, and the code won't even compile as given, producing:
$ javac Test.java
Test.java:13: error: variable account is already defined in method main(String...)
String account = account.nextLine();
^
Test.java:13: error: cannot find symbol
String account = account.nextLine();
^
symbol: method nextLine()
location: variable account of type String
2 errors
This error is because you are declaring a second (String) variable that is also named "account" which shadows the Scanner variable named account.
If I rename these variables it becomes much clearer — the Scanner is where you are getting your input, so I rename this as Scanner input and when you ask about creating an account you are not getting an account, you are getting an answer to the question, so I rename this as String answer.
Initializing answer to be "no" makes the while loop easier (though IRL I wouldn't initialize it, I would use a do...while)
This gives me the result ...
import java.util.Scanner;
public class Test
{
public static void main(String...args)
{
Scanner input = new Scanner(System.in);
String answer = "no";
while (answer.equalsIgnoreCase("no")) {
System.out.println("Do you want to create an account?");
answer = input.nextLine();
}
}
}