A fixed-width file use a fixed column width for each column (though not all columns necessarily have the same width) and pads the remaining space on the left or on the right, usually with spaces:

   287540 Smith  Jones  Accountant         $55,000
   204878 Ross   Betsy  Senior Accountant  $66,000
   208417 Arthur Wilbur CEO               $123,000

This example use golang package github.com/davidburil/fixedwidth