Actually what have shown is a reference to an @array, but assuming that's a typo, the usual method of passing named options to a function in a module looks something like this

module::method( {option1=>value, option2=>somevalue });
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Often the module name can be dispensed with.

In your specific case (without reference to the docs for HTML-clean which I haven't located.) you probably want

HTML-clean::strip( {lowercasetags=>0 })

You could also do it this way.

my %options;
$options{lowercasetags}=0;
HTML-clean::strip( \%options );
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Using the OO style this would look like

my $handle = new HTML-clean(...);
my %options;
$option{lowercasetags}=0;
$handle->strip( \%options );
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You'll need to read the docs for HTML-clean to work out any other parameters and options and where to put them.