I often see this tree on Instagram along with other succulents.
could you help me identify this tree?
It is crassula ovata, commonly known as the Jade plant. They are often darker green, but in bright light conditions the leaf color changes to light green or yellow (as in the OP's picture) because the plant doesn't need to make so much green chlorophyll for photosynthesis.
They are very easy to grow and propagate. A single "leaf" that gets detached from the plant will usually start to grow roots in a few days, without any soil or water!