As long as you don't try too hard or get obsessed with it, exercising every day is fine. Make sure it's something you enjoy without being too hard on yourself, especially during times of illness or injury. Yes, you can work out in the gym every day. However, while exercise is important for staying healthy, so is allowing time to rest and recover.
Going to the gym every day isn't inherently harmful, but it's not necessary to maintain and improve your fitness. While many experts recommend taking at least one day off a week, it's okay to have an active rest day. The 12 best leggings for hot summer workouts. You can also try reducing your time in the gym and instead increasing intensity with HIIT workouts if it's appropriate for your fitness level.
It is also recommended to incorporate some strength based exercises using free weights or resistance gym machines, for example, a leg press. If you're not an elite athlete and are more likely to have to push your body to the limit, daily workouts at the gym, in which you incorporate light to moderate intensity cardiovascular exercises with some strength based exercises, will do wonders for your body and mind.