No. Falkland Islands doesn't ask visitors to fill in an online arrival form (also called an entry form, immigration card or landing card) before they travel. Visitor permit is normally issued on arrival; visitors must give accommodation details to Customs and Immigration.
Do I still need a visa for Falkland Islands?
An arrival form is not a visa. Whether you need a visa or an electronic travel authorization depends on your nationality, so check Falkland Islands's official immigration website or your own government's travel advice.