Child with US passport is travelling to UK, does child have to go for bio-metric? I understand US Citizen doesn't need a UK Visa. But do they have to go to bio-metric?

When we Submit UK Visa Supporting Documents from Sponsor should we submit a original Document or Scanned\Print out copy is suffice? Example Sponser Supporting Document I'm referring are below: Letter of invitation bio-data pages of passport Valid visa or immigration stamp Resident Permit in UK Finan...