I'm Lucy, and I'd be happy to answer your questions today.
As a general rule, a person may not install spyware on anyone else's phone without consent. However, if they're paying for the phone, or if you're using the phone for work purposes, then it could be possible to argue that it's not your personal phone. In that scenario, look at any documentation they gave you to see if, somewhere in there, you've agreed. If your phone is not used for any work purposes and they do not pay the bill as one of your benefits, they cannot install a spyware app on your phone any more than I could. You may want to take the phone to someone who can have the app removed and scan it to make sure there's nothing else you don't know about.
Note that if they say something like "You have to install this app if you want to keep working for us," then you're considered to have consented if you keep working with the company. Because employment is at will, it wouldn't be illegal for them to fire you for refusing to hand over your phone. But in that scenario, you may want to consider whether it's better to have two separate phones, one you use for work-related things, and one you don't. And if the phone is not used for any work purposes, then you also have to think about whether you want to work for an employer who's going to impose that requirement on employees. Once you give them your phone, though, you're considered to have consented.
If you have any questions or concerns about my response, please reply WITHOUT RATING. It's important that you are 100% satisfied with my courtesy and professionalism. Otherwise, please rate my service positively so I am paid for the time I spend answering questions. If you are on a mobile device, you may need to scroll to the right. There is no charge for follow-up questions. Thank you.