You can use LWP::AuthenAgent to ask for authentication. Here's an example. The user is "guest", and the password is "guest":

#!/usr/bin/perl

use strict;
use warnings;
use LWP::AuthenAgent;
      
my $url = 'http://jigsaw.w3.org/HTTP/Basic/';
my $ua = new LWP::AuthenAgent;

my $response = $ua->request(new HTTP::Request 'GET' => $url);
print $response->decoded_content, "\n";
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