Formal:
* Siku yako ilikuwaje? (This is the most literal translation and is considered formal)
* Ulifanyaje leo? (This means "how did you do today?")
Informal:
* Siku yako ilikuwaje? (This can be used informally as well)
* Umekuwaje leo? (This means "how have you been today?")
* Leo imekuwaje? (This means "how has your day been?")
More casual:
* Habari? (This is a general greeting that can also mean "how are you?")
* Umefanyaje? (This means "how have you done?")
The best way to choose the right phrase depends on the person you are speaking to and the context of the conversation.