I would send a mail... How could i do something like this

I've traditionally used Mail::Sendmail for that; although, Mail::Send may also be worth considering.

Note too that it's generally unsafe to allow the user to specify a destination address for mail (unless you have carefully authenticated the user). In simple cases like this, it's often best to hardcode the destination address. In more advanced cases, possible destination addresses can be stored in a configuration file or database that only system administrators can edit, and the user can be allowed to select from among them.