I am making a C#.NET application wherein I have designed an Administrator account. Now to Login in that account the Administrator has to enter the password.
My Ques
Do you have a database in your system already ? Then just put it there. You will probably have a users table, that can be extended to accomodate the password (?) If not, you could store it in a file.
What really matters, is that you should not store the password in plain text. It is bad security practice. You should one-way hash it using a good hashing algorithm (such as SHA512), preferably using a salt.