The current in I1 will be the sum of the current in I2 and I3.
In a parallel circuit, the current is divided between the branches. The total current supplied by the battery is split between the lamps.
Thus, if lamps I2 and I3 are identical, they will draw the same amount of current. If I2 and I3 are different, then the current through each could be either higher or lower depending on its resistance.
In other words, current I1 will be the sum of the currents that will enter I2 and I3
Remember, in a parallel circuit, the voltage across each component is the same, but the current through each component depends on its resistance according to Ohm’s law (I = V/R), where (I) is the current, (V) is the voltage, and (R) is the resistance