Your question could do with some more information, but I think this is what you are looking for:
I constructed this query from the following documentation:
https://codex.wordpress.org/Class_Reference/WP_Query#Date_Parameters
$today = getdate() ;
$mday = $today['mday'];
$days = 2; // Collect post for the last 2 days
$args['date_query'] = array(
array(
'year' => $today['year'],
'month' => $today['mon'],
),
array(
'day' => array( $mday - $days, $mday ),
'compare' => 'BETWEEN',
),
);