How do I get a player's name from an ID? [closed]

Sure. This function will return the username from the given id. :)

function UserFromId(userId)
local userSets = game:GetService("InsertService"):GetUserSets(userId) --get the user's sets
for _,v in pairs(userSets) do --iterate through then
if v.Name == "My Models" then --check if  this is the player's models
return v.CreatorName --returning the name of the creator of the set "My Models" (the player)
end
end
end

print(UserFromId(261))