If you’re new to the NSO Pegasus spyware controversy, here’s a post that’ll get you caught up.
With that in mind, this from The Verge’s Mitchell Clark:
Amnesty International — part of the group that helped break the news of journalists and heads of state being targeted by NSO’s government-grade spyware, Pegasus — has released a tool to check if your phone has been affected. Alongside the tool is a great set of instructions, which should help you through the somewhat technical checking process. Using the tool involves backing up your phone to a separate computer and running a check on that backup.
Here’s a link to Amnesty’s instructions. A bit techie, but not too hard to follow if you are OK using Terminal.