I downloaded an app with a 7 day trial period. after that, it would charge. i uninstalled it. Will I be charged?

I downloaded the 'Picture This' app to my iphone 12. The fine print said it would charge after a 7-day trial period. I never used it. I uninstalled it within the 7-day trial period. My itunes has never been set up to purchase anything. My in-app purchases show that app as free and doesn't have a receipt. I am concerned that the 'Picture This' company will try to charge me somehow. How do I prevent this and cancel a 'subscription' that really shouldn't exist? This is my first time to use an iPhone.