如何设置SQL Server连接字符串?

I'm developing a simple C# application, I'd like to know this: When I connect my application to SQL Server on my PC, I know the connection string (server name, password etc.), but when I connect it to another PC, the SQL Server connection string is different. Is there a common account in SQL Server that come with default account that can connect? I have heard about I'm developing a simple C# application, I'd lik