I have a circuit in where there are 3 different bulbs (circular, oval, and rectangular, the circular is the dimmest, the rectangular is more brighter, and the oval is the brightest. Now , I am wondering is the current the same through the whole circuit and is it different at each bulb? Or how does the current in each bulb compares to the current through the battery?
Current is an amount of charge flowing every second. No new charge suddenly comes into existence during the circuit, so charge flowing from the battery must be shared.
The current can be equal in all of the branches (through all light bulbs). But what if one light bulb resists charge passing through a bit more than the others? Then the others have more charge passing through. You can set up Ohm's law for each light bulb:
They all have the same voltage (potential difference) across them, because they are all directly attached to the battery ends. So if one has a higher resistance than another, $R_1>R_2$, then the current has to decrease to still makes Ohm's law fit, $I_1<I_2$.
Larger resistance reduces the amount of charge that passes through, if the "pressure" or "push" on the charge (the voltage) is unchanged.