I need to have my phone repaired due to water exposure. Where can I have it repaired?

What do you need out of it? If you want an official Apple replacement, they will only replace the entire device for an out of warranty replacement fee. That obviously means the data is gone and Apple will most likely just recycling the exchanged iPhone.

If your situation is "It doesn't work and I desperately need the 5 years of photos that I never backed up" then that's another matter. There are some repair shops that can do data recovery work by tracking down whatever is not working and then putting in fixes that allow recovery of the data. But not usually in any way where your iPhone will be usable long term.

Hello ~ Take a look here:

Genius Bar Reservation and Apple Support Options

~Katana-San~

Apple won’t work on a water damaged device.

They will most likely offer an out of warranty replacement.