well my japanese is not good but as i know "ogenki desu ka" means " are u ok. (healthy) ? " how are u today : should be " kyo wa ikaga desu ka ? " today = kyo how , in what way = ikaga

Although there are many small variations of course - the most simple and common would simply be "O-Genki desu ka?" 「お元気ですか？」. It technically means simply "Healthy?" but it has the meaning of "Are you well?" or "How are you?".

Kyo wa ogenki desu ka?