Holding a multimeter with bare hands? What will happen you'll hold both the metal part of the ends of multimeter each with one hand and check the voltage/current/resistance? While standing on insulated surface and ground both. Will the current pass through one hand to another? What will happen exactly?
 A: This is a great question.
For resistance, you'll get a perfectly valid reading of the resistance of your body between those two points. This value will probably be dominated by the resistance of the dry skin at the points of contact. (The high resistance of dry skin is the reason why electrode paste exists.) If the resistance is too large for your voltmeter to handle, it will display some kind of error message or out of range indicator.
For current, you should get zero. Your body is a good insulator, and there is no voltage big enough to drive a significant current against that large resistance. If any current flows, it will be in the picoampere range or less, which a handheld multimeter can't sense.
For voltage, this will depend on the exact type of voltmeter and what it's designed to do. One way of modeling some types of voltmeters is that a voltmeter is an ammeter in series with a large resistance R. The meter is then able to measure voltages provided that other resistances in the circuit are small compared to R. If your multimeter is implemented in a way that is well described by this model, and if your body's resistance is not small compared to R, then you will get a reading, but it will be inaccurate (low).
