If you want the values of @array to be the keys, then your example hash would look like this:

%hash = ( "var1" => "Info on var1", "var2" =>, etc....);
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Without knowing any more about your problem than what you've stated, here's what I would do:

my @array = ("var1", "var2", "var3");
my %hash;

foreach my $item (@array)
{
  $hash{$item} = "Info on $item";  # or <STDIN> for user input
}
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Edit:
Your use of the word key is somewhat confusing. Either you want to use the user input as key in a "many to one" mapping to the items in @array (which hotshot's answer will get you) or you want a "one to one" mapping where the keys are the items in @array and each one maps to some user input (which my answer attempts to do). Only you know what it is you need, so use that! :) ~CubicSpline
"No one tosses a Dwarf!"