Formal:
* Geniet jou dag. (This is the most literal translation, meaning "Enjoy your day.")
* Hê 'n goeie dag. (This means "Have a good day.")
Informal:
* Lekker dag! (This is a common and informal way to say "Have a nice day!")
* Geniet! (This means "Enjoy!" and is a very casual way to say have a great day.)
You can also use phrases like:
* Totsiens en 'n goeie dag! (Goodbye and have a good day!)
* Hê 'n wonderlike dag! (Have a wonderful day!)
The best choice will depend on your relationship with the person and the situation.