Anyone know what the largest tire and which fender will work with this bike? Ive been searching and googling and didnt find anything

i ordered this today as my new commuter:
https://www.trekbikes.com/us/en/bikes/road/1_series/12/

Something like SKS raceblades will work. Full fenders will be a challenge. As far as tire width goes, 28mm tops but maybe not even that.

yeah im getting a bunch of conflicting reports, thats why im hoping someone attempted something
if i can run 25s and fenders ill be happy, but im hoping to find someone that has tried something and it worked so i can just get what they got

25s for sure, possibly 28s. I doubt anything larger though. That's without fenders. For fenders, raceblades should fit, but I don't know how effective they are.

I added a longer mudflap to the front raceblade and it works well enough for keeping the spray off myself and off the drive train. It won't keep grit out of your front brake mechanism or headset.

It's probably worth mentioning though that the cantilever brakes that you often find on bikes with clearance for wider tires aren't protected even by full fenders. In fact, fenders probably end up directing even more crap at them.

They get rain in Saudi Arabia?

yeah, it just flooded actually...
im moving to japan in march

A Trek 1.2 has long reach brake caliper, so there is quite good clearance for at road bike. It even has eyelets for fenders, so you can put on full fenders. Along with these, you can at least mount 25mm tires, 28mm without. Maybe even 28mm with fenders, if you heat up the fender a bit and fit it tight. I haven't tried this, though, but 25mm + fenders i definitely possible.

For full fenders, you need a 35mm wide version. Many make them, SKS are best known.

im still wary about "should" fit
when im ordering almost 200 (after shipping) im tires, tubes, and fenders, id like to know it fits ya know?

Then go with 25mm tires and 35mm fenders. I'm 100% positive it fits. For your next set of tires, make your own judgment whether 28mm will be possible.

Do you have the bike now? Then I would get the full fenders and see how much clearance you have with the stock tires. Then you can decide if 25s or 28s will work. Beware though that tire manufacturers are pretty fast and loose with their advertised sizes. One 28 may fit while another won't.