Voltage to current conversion
In low voltage applications, it is assumed that both voltage &amp; current
  carries information instead of energy.


No, voltage and current always "carry" energy one way or the other.  Sometimes more, sometimes less, but in order to "carry" information they have to "carry" energy as well.  The amount of energy required is a function of the amount of information transferred
 and the characteristics, particularly noise level, of the channel.  This is basic information theory.


  So how is it possible to transform the information carried in the form
  of Voltage to Current without altering it and vice versa?


A resistor would do this, but you may be thinking of a transconductance amplifier.  What is your goal in implementing this?


  for eg: If one of the terminal of 1k resistor is connected to 5V
  source &amp; another to Input pin of any IC let’s say then:
  
  What is the Voltage &amp; current at the input pin of that IC?


That depends on the input impedance, bias, etc. of that IC.  In most cases, IC inputs (analog or digital) will be a relatively high impedance, so you'll see 5V at the IC input with very little current.  However, you should check the specs on the particular part you're using.