Querying multiple values from a single key

Just add 'compare' => 'IN':

        'key' => 'document-type',
        'value' => array( 'Install Manual', 'User Manual' ),
        'compare' => 'IN'

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)