Water

Yes, except alcohol.

It's considered hydrating enough to count. Whether you want to log it as water depends on your personal goals and preferences.

When I was trying to make sure I got enough water alongside my daily eating/drinking fluids, I just logged water in the water section, because water was what I cared about.

Water isn't dramatically meaningful for weight management, except to the extent that some people find that drinking more water helps curb appetite.

Hydration - total from all sources including not just drinks but fruits, soups, etc. - is important for health, but there's no universal goal amount. It varies by person and situation. Example: I sweat lots, so I need more hydration on a day when I take a long bike ride in hot weather.

If urine color is pale yellow, hydration is likely OK. Urine can be bright but still pale neon yellow, for example from getting more than needed of certain B vitamins. Being dark or brownish usually suggests under-hydration. Some other colors can happen with health conditions or certain medications.