Fixture not to exceed 100 watts, it has 3 light bulbs,not to exceed with all 3 light bulbs combine or each light bulb

Usually each lamp holder (socket) has a maximum rating, you may have a fixture with a max rating. Where is this label?

All bulbs added together can not exceed the 100 watt rating of the fixture. So each bulb can not be more then 33 watts a piece.