Hello,
Using Automation Anywhere, you can create a list variable that can read value from a text file. Either you can assign pre-defined comma separated values in a text file or using 'Log to File' command, you can log the values at run time. Using 'Loop $ListVariable$' command, you can access these values later in the task.
For better understanding, you can refer to following online example,
http://www.tethyssolutions.com/T12.htm