Make a list of which (first ...) and WHICH (First ...) so that you generate the CGI parameter names on the fly. Store questions and answers in arrays. I have rewritten part of your code to show you how this is done.

#!/usr/bin/perl -w
use strict;
use CGI qw(:standard);

my @which = qw/ first second third fourth fifth /;
my @WHICH = qw/ First Second Third Fourth Fifth /;

print header, start_html("Quiz Maker"), h1("Quiz Maker");

if (param()) {
    my $who = param("firstname");
    my $who2 = param("lastname");
    my $email = param("email");

    my @questions = map { param("$WHICH[$_]Question") } 0..4;
    my @answers = map { param("Answer$WHICH[$_]Question") } 0..4;
    #my @user_answers = ...     # you get the picture
    #my @choices = ...

    print p("Thank You. Here is your quiz:");
    print p("Name: $who $who2");

    for (0..4) {
        print hr(), start_form();
        print p("Question #". $_+1 .": $questions[$_]");
        print p("Answer:", textfield("UserAnswer$WHICH[$_]Question"));
    }

} else {

    print hr(), start_form();
    print p("What's your first name?", textfield("firstname"));
    print p("What's your last name?", textfield("lastname"));
    print p("Enter your e- mail address", textfield("email"));

    for (0..4) {
        print hr(), start_form();
        print p("What is your $which[$_] question", textfield("$WHICH[
+$_]Question"));
        print p("Please enter the answer", textfield("Answer$WHICH[$_]
+Question"));
    }

    print hr(), start_form();
    print p(submit("Submit"), reset("Reset"));
    print end_form(), hr();
}

print end_html;
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