The terrariums or gardens in a bowl are compositions that do not require a lot of care, even so, you must take into account some light factors when choosing the place where you are going to place them. These compositions are home to plants that thrive in environments with high humidity.
Mosses, ferns, ficus, phytoniums and other tropical plants are very common choices for this type of environment, here are some specific guidelines for providing them with the right light!
Bright indirect light: Terrarium plants prefer bright indirect light. Prolonged direct sun exposure can be too intense and increase evaporation too much. It can also dry out the moss in your terrarium.
Light duration: Make sure plants receive 12-16 hours of light per day. In indoor environments, you can supplement natural light with plant-specific artificial lights.
Continuous monitoring: Keep a close eye on the plants' response to light. If you notice them stretching toward the light source, it's a sign that they need more light. On the other hand, if you see signs of leaf burn, adjust the distance of the lights to reduce the intensity.
Rotating the terrarium: Rotate the terrarium occasionally to ensure that all plants receive an equal amount of light. This prevents a section of the terrarium from becoming more dense and shady due to the fixed position. It also prevents the moss from becoming lighter in certain parts.
. 
The key to keeping your terrarium perfect lies very much in providing the right amount of light. With bright indirect light, adequate duration and moderate intensity, you can create an ideal environment for the development of these small ecosystems. Here is a video we have on Youtube that explains very well the care of terrariums or gardens in a bowl!