If you go to a Genymotion virtual device's settings, there's no user icon!
Are multiple profiles / users supported in Genymotion?
You have to enable it via adb.
Try the following commands:
adb shell
su
mount -o rw,remount /system
echo fw.max_users=4 >> /system/build.prop
echo fw.show_multiuserui=true >> /system/build.prop
exit
Restart genymotion after that. If the users menu doesn't appear in setting immediately after restart you will want to add at least one user manually through adb.
adb shell
su
pm create-user <username>
exit
Restart after adding the user. The users option under settings should be visible now.