The OMI Wallet only appears in the Google Play Store version of the VeVe app.
As a result of Apple's requirements, the OMI wallet is only available in-app in the version of VeVe available in the Google Play Store.
If you want to send and receive OMI and you're an Apple device user, you can use the web wallet at https://omi.veve.me
Learn more about storing OMI from our article Where Can I Store My OMI Tokens?