Hello, I try to make my character take objects from the floor. I have the idea how to do but the question is when the object should take the location of which is related to emty hand bone. Can anyone tell me how to do this.

I've had some ideas about this.
First you need to parent the object to the hand (the hand armature if you can) or an empty next to the hand.

I've notice in some games that when the player takes things they do a swiping motion (the grab animation) and then their hand raises with the object

the quick motions will hide anything funny. For example if you have it set up to grab a water bottle perfectly, but later want the player to grab a ball or another object, the quick motion of the hand and the swiping/grabbing sound will trick the mind into thinking you grabbed it, even it the animation didn't go perfectly (like the ball was to big for the hand or not close enough for an actual grab)

I hope this helps