To copy variable's value into a journal type field

Hi Community,

I have few select box variables, if user selects the value of those variables as rejected, rejection reason field will populate. I want to copy the value of those variables if they are rejected along with the rejection reason from sctask to another table's journal type field.

I am thinking about the logic like if xyz == rejected && rejection reason != '' then need to add them in that journal field. If those are not rejected, those i approved i dont want to add them in this journal field.

Thanks,

Poorva Bhawsar