Despite being a Wise user for more than 5 years, I've only just realized the web version offers details on the volume discounts but the iOS app version does not!
This seems like a very important missing feature for the iOS app to have IMHO. The only reason I used the web version was because there was an issue with the Wise iOS app that I was trying to troubleshoot on behalf of Wise customer support - which is excellent in responsiveness in my experience.
To view the discounts - which can vary between currency pairs - click on your profile in the top-right corner of the Web version of Wise, then you will see Pricing and discounts.

After clicking on Pricing and discounts, you will see your eligibility for further discounts and what the volume-based rates are as shown below.

Takeaway
Wise has a strong promise around being transparent with fees, but I feel like this missing feature is a miss on that promise. I hope Wise addresses this in an upcoming release.
I would also like Wise to reintroduce a % fee display when performing a transfer. When the fee as an amount, but the discounts are shown as a % in other places, it makes it harder for the user to trust they are in fact getting a discount or they are getting a good rate.
Discussion