How is the effect of bathroom glass stickers? Could you please tell me?

The better one on the market is Lung film, but the price is relatively high and is available in shopping malls.

Be sure to use professional staff, otherwise there will be air bubbles.

1. After applying the sticker, it should be fine during the day, and you can’t see the inside from the outside. But at night, when the lights are on at home and it’s dark outside, whether you can see clearly

It depends on the specific material of the sticker.

2. When it comes to stickers, do I need to put them on the outside of the windows, or only stick them on the side at home?

Just stick them on one side.