One way is to put your sub into a module and import the sub into your script. See Simple Module Tutorial for more information.

#!/bin/perl5

use strict;
use warnings;
use lib qw{local/lib};
use Article qw{article_layout};

layout();

sub layout {
    #...
    my ($headline, $body, $url) = qw{one two three};

    article_layout($headline, $body, $url);

}
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package Article;

use strict;
use warnings;

use Exporter;
use vars qw($VERSION @ISA @EXPORT_OK);

$VERSION     = 1.00;
@ISA         = qw(Exporter);
@EXPORT_OK   = qw(article_layout);

sub say {
  print qq{$_[0]\n};
}

sub article_layout {
  my ($title, $body, $url) = @_;

print <<HEADER;
header stuff
HEADER

say $title;
say $body;
say $url;

print <<FOOTER;
footer stuff

FOOTER

}

1;
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output:

header stuff
one
two
three
footer stuff
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