Where is the ark tab

i have downloaded the unreal engine 4 and signed in but there is no ark tab

You on a Mac?

https://forums.unrealengine.com/development-discussion/modding/ark-survival-evolved/71076-ark-dev-kit-mac?99248-Ark-Dev-Kit-Mac=

There is no ARK tab anymore, however ARK: Survival Evolved is the first option in the list under the Modding tab. The modding tab is only available on the Windows version of the Epic Games Launcher.