I will try and post here the solution 

My question how to display the result of the query on CMSB  ListPage Fields and what should the field type

I tried using separator field as below code

<?php
$date1 = new DateTime(@$RECORD['createdDate']);
$date2 = new DateTime(date("Y-m-d H:i:s"));
$interval = $date1->diff($date2);
$days=$interval->days;
?>

<input type="text" style="width: 100%" name="lock_period" value="<?php echo $days;?>" readonly class="text-input form-control" data-dirrty-initial-value="">

its return the value in edit page as expected but didn't displayed on in the list page

Please find attached screen shot for more clarification 

How to display number of days from creation date till today in the ListPage Fields 

Like below example:

Record No.      Creation Date     No. of Days
-------------------------------------------------------------------

     1                   2023-08-01              5

No. of Days=   NOW() - Creation date