Fat loss/calorie deficit

Currently maintenance calories is 1900 calories. In order to lose weight/fat would I have to eat for example 1500 calories and do excercise(burn 500)

Or is eating 1900 calories and excercising(burn 500) still making me in a deficit.

I would like to know if they are both a deficit and one is just faster than the other or if only the first one is a deficit.

My health app/watch etc tells me I burn 1900 calories at resting.