It depends on your gear and your camera’s settings. Ideal aperture to use indoors would be anything between f/2.8 to f/1.8. A lens I’ve used for shooting indoors is the 70-200mm f/2.8. As for the settings, you may need to increase your shutter speed or have assistance from a tripod if allowed. The problem with increasing the shutter speed is it cause pictures to come out darker. I shoot in reptile houses and luckily most of the animals aren’t moving too much, so I can afford to shot at 1/60 and manually focus on my subject when needed