Its just one coin in any world

Well we are assuming that there is little air resistance and the coin is tossed vertically. You and the train are going at a constant, so the coin will as it is flipped. $\therefore$ the coin will land in your palm. This is sometimes called the "cannonball principle".

Due to inertia it will cover the same distance as the train, if we neglect air resistance.

Another question earth is moving with uniform velocity and you jump on earth where will you land America, Europe, Indian Ocean

The coin and the man both would have same horizontal velocity and the frame of reference is not accelarated(train is moving with uniform velocity)

Due to inertia it will cover the same distance as the train, if we neglect air resistance.

The inertia of the coin will keep it moving at the same speed as the train and the passenger, therefore it will fall as it would in a motionless train.

Unless the train is in a curve, the trajectory of the coin, from the point of view of the person throwing it is going to be up and down as both, person and coin, are in the same system of reference.

Since the train is in uniform motion it is a inertial reference frame, thus all the physics laws are behave exactly like any other inertial frame of reference (like the train station).

Since the coin is moving with the train, the velocity of both is the same, therefore when tossed, the coin should have no additional starting velocty on the horizontal axis (assuming the passenger did not throw the coin horizontally, and hat air resistance is negligible). That being stated, the coin should land back into the person's palm. However, from the passenger's reference frame, the coin travels up and back down into the person's palm.

You, the train, and the coin all have the same horizontal velocity.

The frame of reference is the same. Whether you are enclosed in a compartment moving at a constant velocity or whether you are stationary on the ground.

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it will land in his hands because if the car train is moving with a velocity $v$ then the will also be moving with the same speed after being tossed .

the train and we are going with same velocity and other work done by inertia

in simple words I would like to say that the phone and the person move with the car with the same speed they gain some momentum due to which even as they leave contact from the car instantly there there will be no change in this speed so when the person will throw the coin upwards person and the coin will move with the same speed horizontally instantly and so the coin will fall on the palm of the person.