How to send a friend request via game???

Here is what I have:

script.Parent.MouseButton1Click:Connect(function()
	if game.Players.LocalPlayer.Name ~= script.Parent.Parent.TextBox.Text then
		game.StarterGui:SetCore("PromptSendFriendRequest", script.Parent.Parent.TextBox.Text)
	end
end)

But it only lets me send if the player is in the server. I want it so it sends to their friend request inbox thing on the website.

EDIT: I found this website thing with the Roblox Web APIs. I found one for making a user send a friend request but have no idea how to use it. It can be found under Domains > Friends API > /v1/users/{targetUserId}/request-friendship. How on earth would I use it???