How can I insert a model via script?

What You Need

The LoadAsset function of InsertService

The LoadAsset function takes in arguments of the model ID that you're importing. If you pass all the prerequisites(which I will state) then it returns a model instance, your model that you're importing is inside of this model.

NOTE: The model is initially nil, you have to parent it to workspace for it to show up. (Credit to LordDragonZord) You can either do this by directly setting the Parent property of the model, or using the Insert function of InsertService.. which basically just does the same thing as the former.

Prerequisites of LoadAsset

The model has to be either owned by;

• The owner of the game you're importing to

• The ROBLOX account

Code

local is = game:GetService('InsertService')
local id = 00000000 --ID of model to import

local model = is:LoadAsset(id)
model.Parent = workspace

--Or (Credit to LordDragonZord)

is:Insert(model)