"Add seasoning" is a phrase that you can use to describe the action of adding additional flavors to a dish. Here are a few other phrases that you could use to describe this action:

"Season the dish"
"Flavor the dish"
"Spice up the dish"
"Add some zing to the dish"

For example, you could say "I'm going to add some garpc and parsley to the dish to give it some extra flavor." or "I'm going to season the chicken with a pttle bit of paprika and cumin."