My text forwarding option in iPhone 6 is not showing up after update to iOS 8.4.1

What text forwarding option?

Please clarify.

Do you have another device logged into the same Apple ID that you can forward them to, such as an iPad?

This option is gone as of the latest iOS update on my iPhone 6 as well. I stopped receiving SMS texts on my Mac as of August 25.

I don't know if this will help you. I had the same issue. On my iPhone I went to Settings > Messages > Send & Receive. I then clicked on the Apple ID email address at the top of the screen and selected "Sign Out" from the pop up window that opens. Once I had signed back in the "Text Message Forwarding" option was back and I was prompted to enter a code from my Mac.