Go to www.camrystuff.com
I think your 99 is generation 4, but I might be wrong.

Download your car's repair manual and get all the answers from there.

Good luck,

Sam

Replace with the engine cold. This was not too much of an issue with
older iron blocks. A dab of antiseize to the plug threads (3 threads
away from the tip end). Dielectric grease on the rubber boot. These
help future removal.

Use NGK Iridiums. (-IX or -Laser). Good stuff. I'd stay away from
Denso plugs, not even Toyota's racing team wants them (they used
Bosch).

Just a simple question.....
Why do you want to change plugs?
The reason I ask is that I have a '97 Camry 4 cyl. with 142,000 miles on the
clock.   I bought it as an ex-Hertz rental in 1998.    I have changed oil
and filter regularly (every 6000-7000 miles) and had the timing belt and
water pump changed at about 110,000 miles, but unless the plugs were changed
by Hertz in the first year of their ownership, they are the original plugs,
as are the wires.
The engine runs smoothly, with no misses and no coughs, starts instantly,
and so on.  I see no reason to change something that appears to be working
like new.
I'm sure lots of folks would say this is "poor maintenance" but is it?