Opened suspicious pdf that was texted to iPhone

My husband received a text from an unknown sender and clicked on the pdf that had been sent. He showed it to me (something about a toll violation, which is impossible as he doesn’t have a car), and I immediately shut down his phone. I’ve restarted the phone and disconnected it from our home network. I also deleted the message and reported it as junk. Hopefully it will delete from his MacBook as well, but I will check that soon. Is there any way his phone has been infected? What more can I do to insure its safety? He’s using an iPhone 13 Pro which is updated to 18.3.1.