Host or Accommodation for family reunifican

On long term visa form there is a checkbox which says:
"Has the inviting person signed an official document with a commitment that charge will be taken and has this document been validated by the host country?"

Should i check this check box? if yes do i need any additional document or can leave non mandatory fields empty (Person number, Identity document number)

UN-checked:
https://i.ibb.co/vH1F9bc/Screenshot-2020-02-25-at-11-11-01.png

Checked:
https://i.ibb.co/P4yzxCY/Screenshot-2020-02-25-at-11-11-33.png

Answered here:
https://www.expat.com/forum/viewtopic.p … 03#4806460