There are a number of ways to do it, which is best for you is going to depend on how you are displaying the info, and where you are sourcing it.
If you are sourcing the data from a database, then the easiest way is to read the information into a DataTable, and use that as the DataSource Property of a DateGrid or DataGridView.
If you need it displayed on the console, then just using the format length specifiers may be enough:
string TestId = "1";
string ApiName = "abc";
string ActualOutPut = "asdfsa";
string ExpectedOutPut = "sdfsdf";
Console.WriteLine("{0,8} {1,8} {2,8} {3,8}", TestId, ApiName, ActualOutPut, ExpectedOutPut);