I just got an iPhone the other day and I'm confused with the iMessage?

I sent an iMessage yesterday on IPhone but today realized that it failed to send, if i resend it today will it show up (to the person that i'm sending it to) as yesterday or today?

Will show up as today. If it didn't send through imessage, it likely sent as a regular text, so will show as a duplicate.

Today. Since it never sent before.