The Female Elk do not have any antlers.
Only the male Elk have antlers so if you see an Elk without antlers then it likely is a female Elk and if you see an Elk with Antlers it's always a male Elk.
That is one easy way to tell whether an Elk is female or male is to look for antlers.
If the Elk has Antlers It's a male Elk and if you see no antlers then it's a Female Elk.
An Elk's antlers are much taller than a deer's antlers.