title: How to autofill date in google sheet when i enter value in cell A
body: <p>If I enter "paid" text in cell A in sheet, I want to auto pull the current date in cell B. If the cell is empty, it should not pull the date.  Like:</p>
  
  <pre><code>--------------------------------------
  A           |  B
  --------------------------------------
  Paid        |  2/25/2018
  ----------------------------------
  Paid        | 2/26/2018 
  ----------------------------------
  empty cell  |   
  ----------------------------------
  empty cell  |  
  
  
  
  
  I tried to use =ArrayFormula(IF(A2:A81=paid),"paid",(NOW())) 
  </code></pre>
  
  <p>But getting error. Is their any way to do it?</p>