i just want to know whether i can make my digital pins produce voltage constantly like a power output pin
Yes, you can. But you need to limit the current to 20~30mA at most.
What do you want to power from a pin?
a coreless motor, is it safe to do
Does this motor draw more than 20~30mA?
Consider that all motors draw 5~10 times their normal level of current when starting up or stalled.
yes it does draw 100mA, soooo.... its not possible to connect it right?
Correct - google 'drive motor with Arduino' - lots of links on how to do it correctly.
actually it adds weight which i dont want
What adds weight?
How much is too much weight?
Do you need to control the speed of this motor?
Do you need to control the direction of the motor?
Please post a link to the technical specs of the motor.
What you can do, is run the motor on limited power. Put a 220 ohm resistor in series with the motor. Now it's safe from the Arduino point of view, your motor may or may not have enough drive with that. Start up torque is greatly reduced when there is resistance in the supply.
You should use a transistor to drive the motor. Weight? A bag of 1,000 MOSFETS is probably only a few grams. You only need ONE.
Not quite safe, a flyback diode must also be added to protect the Arduino from the negative voltages generated when the motor stops turning (assuming it will turn at all with 220R in series).
The flyback currents are not likely to exceed the drive current, I haven't done a deep dive, but it seems to me it could be safely absorbed in the GPIO clamp diodes.
Having said that, it would be super easy to add a flyback diode. 
I have played with similar motors, and many of them will run on incredibly tiny currents. Not enthusiastically, but they will run.
Your motor is rated at 3.7V. Most Arduino run at 5V, so there is a danger of damaging the motor. But without extra driving circuitry, almost certain damage to the Arduino.
What model of Arduino do you plan to use?
Will my previous questions be answered?
i need to control the motor's speed
am using an arduino uno
They basically stole that spec from the LiPo spec since it's for drone use
so its good or bad
Peppering us with additional questions when you haven't answered ours, won't fly.
Do you need full power from the motor?
yea sry about that and what is ur question
Go back, there are multiple questions for you. Just review them all slowly, and answer them all in one post
Take your time, put on a pot of coffee or whatever you need to do to stay focused.
no 3.7 v works fine