That shows the CapCut page and as with any free trial I have seen, it is only for new subscribers and may have been disclosed in the Terms you agreed to by tapping, so not sure if that is the case for you or not. After you click the Purchase button in the app, then you are brought to the Apple payment screen where the subscription start date should have shown today with the price you would be charged, if you previously used the free trial. If you had not used a free trial before, then you should see the trial period, then the subscription start date showing 7 days later. You should have seen that before you double clicked the side button to agree to the charge.
Of course there are many people who try and use free trials multiple times and find out it is not possible and are not happy about it. I can go to the Paramount+ website and it says that there is a 7 day free trial, but if I signed up for a subscription with them I will be billed instantly since I had already used a free trial. They do disclose that in their terms here, but not sure if CapCut is as forthcoming in their disclosures:
Your Subscription may start with a free trial period. Free trial periods are available to new subscribers only.