I agree with the previous, the 4 petal flower is absolute confirmation that this is a holly, Ilex, and the leaves strongly suggest Ilex crenata, or Japanese holly.
Japanese holly is moderately common as bonsai. It is an evergreen shrub, more or less sub-tropical. Or rather, living between Chicago & Milwaukee, I would consider it a subtropical shrub. It is not quite winter hardy in my area. It will take some cold, it has naturalized and become an invasive species in southeastern states of USA. I suspect it is hardy through USDA zone 7, no colder.
When grown as bonsai it is usually protected from freezing, especially if in a ceramic bonsai pot. The protection from freezing is as much to protect the pot from being ruptured by the expansion of the frozen potting media as it is to protect the tree.
Japanese holly need bright light, from very bright shade outdoors to full sun outdoors. Growth is best with at least a half day of direct sun. Indoors, because the glass in a window cuts out a minimum of 30% to as much as 70% of the light, indoors Japanese holly should be in a "full sun" south window. Good air movement is needed to keep the leaves and pot cool while in direct sunshine, indoors it is helpful to have a fan keeping air moving in the vicinity of the tree. A ceiling fan in the same room is usually sufficient. Or an inexpensive fan blowing in the general direction of your bonsai. Good air movement will help most of you indoor houseplants.
Japanese holly do not want to dry out completely between watering. The ideal is to take the plant to your sink, flood the pot with water, let drain, then return your holly to the windowsill where it is growing. Check daily to see if it needs water, only water when it needs it. Dig your finger into the mix, if it is bone dry, it should have been watered yesterday, if it is just barely damp, perfect time to water, if it is still moist to wet, check again the next day. It is important to check moisture daily, as the schedule will change as the weather, humidity and temperature change indoors and out. In warm, low humidity times, the tree will dry quickly. During high humidity rainy and cool periods, the tree will dry slowly. So check daily, as the watering schedule will vary.
