If you are trying to meet a daily quota of fluid, then any flavored beverage also counts - it isn't restricted to just pure water. The original guidelines said 'fluid' but that confused many people, so doctors found it easier to just say water. Now that seems more confusing
Even many foods contain water, and your body recognizes the fluid in it. So yes, your tea counts as water.
But like others mentioned, some beverages contain ingredients that you may not want to put in your body, so read the labels carefully.
Many years ago, I hated plain water. I almost thought it made me nauseous! However, it's all I drink now, other than an occasional cup of tea (no sweetener). I filter my water and keep it in the fridge, and also use filtered water for ice. It's super refreshing and I refill all day.