How can I add a space in between two outputs?

Add a literal space, or a tab:

public void displayCustomerInfo() {
    System.out.println(Name + " " + Income);

    // or a tab
    System.out.println(Name + "\t" + Income);
}

You can use System.out.printf() like this if you want to get nicely formatted

System.out.printf("%-20s %s\n", Name, Income);

Prints like:

Jaden             100000.0
Angela            70000.0
Bob               10000.0

This format means:

%-20s  -> this is the first argument, Name, left justified and padded to 20 spaces.
%s     -> this is the second argument, Income, if income is a decimal swap with %f
\n     -> new line character

You could also add formatting to the Income argument so that the number is printed as desired

Check out this for a quick reference

System.out.println(Name + " " + Income);

Is that what you mean? That will put a space between the name and the income?