Generally speaking, a function dispatch table:

Win8 Strawberry 5.8.9.5 (32)  Wed 07/14/2021 23:52:13
C:\@Work\Perl\monks
>perl

use strict;
use warnings;

my %func = (
    foo => sub { print "fooble: @_ \n"; },
    bar => sub { print "barble: @_ \n"; },
    );

my $from_form = 'foo';

$func{$from_form}(42, 'zot');

^Z
fooble: 42 zot
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Update 1: It's usually wise to check if the $from_form string actually exists in the %func dispatch table before trying to invoke it. :)

Update 2: In Perl as in life, there's usually more than one way to do something. Another way to do what you want is called "symbolic referencing", also known as a "soft reference". This technique is Officially Frowned Upon. See Why it's stupid to `use a variable as a variable name' and also the perlfaq7 FAQ How can I use a variable as a variable name?