I phone hacked

I don’t go on sites that I don’t know, how do i know if my phone is safe as I have removed every save password of the password tab in settings as each time I went to update an password some random email address appeared before I could update so I deleted everyone of them.

I was updating my details on my I phone for Kayo tv and a link popped up and it. Would not allow me to do anything and when o turned my phone off and back on I got another message pop up