my %replace = (
    iapw_p1 => "P1 = (inquiry, launch page)\n",
    iapw_p2 => "P2 = (car coverages, endorsements, operators)\n",
    iapw_p3 => "P3 = (notepad, scratch)\n"
) ;

while ( <> )
{
    foreach my $key ( keys %replace )
    {
        s/$key/$replace{$key}/g ;
    }
    print ;
}