How do you say how was today in French?

There are a few ways to say "how was today" in French, depending on the context and the level of formality:

Formal:

* Comment s'est passée votre journée ? (This is the most formal and polite way to ask.)

Informal:

* Comment était ta journée ? (This is a casual way to ask, used with friends or family.)

* C'était comment, ta journée ? (This is a more informal way to ask, used with friends or family.)

* Comment ça a été aujourd'hui ? (This is a more general way to ask, not as formal as the first option but still polite.)

You can also say:

* Qu'est-ce que tu as fait aujourd'hui ? (What did you do today?)

* Tu as passé une bonne journée ? (Did you have a good day?)

The best way to choose the right phrase depends on the person you are speaking to and the context of the conversation.