Is it possible to send 2 or more o/p signal at the same time?
Technically, it is possible to start two PWM outputs at the exact same
time on an Uno or Nano. If they are both controlled by the same timer,
you just have to update the corresponding control register once with
the relevant bits set to enable both channels. For example, you could
start outputs 5 and 6 simultaneously, as both are on Timer 0:
OCR0A   = value;  // set the duty cycle on OC0A = digital 6
OCR0B   = value;  // set the duty cycle on OC0B = digital 5
TCCR0A |= _BV(COM0A1) | _BV(COM0B1);  // enable both outputs

If the outputs are on different timers, it is a bit more tricky. Timers
0 and 1 can be synchronized by clearing their shared prescaler with the
Timer/Counter Synchronization mode active. I do not think there is a
simple way to synchronize Timer 2 with any of the others.
All this is highly hardware-dependent, and not supported at all by the
Arduino core library. Thus, if you want to apply any of this, you will
have to study the datasheet, and poke directly into the I/O
registers of the microcontroller.
But then, as Delta_G clearly points out in his answer, all this is
irrelevant to motor control. Motors are mechanical devices that have
significant inertia. They take time to speed up and slow down. Just to
give you a sense of scale, PWM outputs 3, 9, 10 and 11 deliver a square
wave with a period of 2.04 ms. Yes, those are milliseconds, and
this is too short for the motors to significantly change their speed
within one period. Contrast this with the handful of microseconds,
that the call to analogWrite() will take.