First go to Development>Data and Parameters>Local Menus-messages. Create a new menu giving it a unique number and define the list of values that will contain the list of option that you want to offer.
Then go to Development>Script Dictionary>Reports. Click on the Parameters tab and define a new parameter. The type should be 'M' and the menu should be the menu number that you defined in the last step. Define the list of values that you want to use.
Optionally, you can go to Setup>Default Values and add the parameter there.
Finally, open the report and create a parameter name the same as the name that you defined in step 1.
I hope this helps.

Thank you for the reply!

This option will be perfect if we are creating a parameter with predefined values. How about populating values from a table?
In this case I want to give them an option to select a range of intercompany Journal entries.

Thanks!

Not sure. There may be a parameter type that allows you to pick dynamically from a table, but I have never explored that. Good luck.

Thank you! It worked!