No, it's just that Useful functions are functions made by the community and that are not built-in into MTA.
To use them, you have to copy the function code first. And then you can call it (the function source code is lower on the wiki page: https://wiki.multitheftauto.com/wiki/DxDrawTextOnElement
local randomPed = createPed(285, 2476.91406, -1665.31799, 13.32435)
addEventHandler("onClientRender", getRootElement(),
function()
dxDrawTextOnElement(randomPed, "SWATTEAM Officer", 1, 20, 0, 0, 255, 255, 1, "pricedown")
end)
-- Function source copied from wiki https://wiki.multitheftauto.com/wiki/DxDrawTextOnElement
function dxDrawTextOnElement(TheElement,text,height,distance,R,G,B,alpha,size,font,...)
local x, y, z = getElementPosition(TheElement)
local x2, y2, z2 = getCameraMatrix()
local distance = distance or 20
local height = height or 1
if (isLineOfSightClear(x, y, z+2, x2, y2, z2, ...)) then
local sx, sy = getScreenFromWorldPosition(x, y, z+height)
if(sx) and (sy) then
local distanceBetweenPoints = getDistanceBetweenPoints3D(x, y, z, x2, y2, z2)
if(distanceBetweenPoints < distance) then
dxDrawText(text, sx+2, sy+2, sx, sy, tocolor(R or 255, G or 255, B or 255, alpha or 255), (size or 1)-(distanceBetweenPoints / distance), font or "arial", "center", "center")
end
end
end
end
^ Like this, your script will work