Secure my browser or iCloud id

What is idmsa. It’s a pop up on my iPhone from Apple asking mebif I want to use idma.apple- or Touch ID to log in as my Apple ID... I found spyware file in my backup downloads & deleted the file. I’m trying to figure out how they accessed & track it to a stalker. But idk if he already has had access to my SIM card. I’d like to track it & I just dkw Apple would ask me if I want to use anything else other than my id unless this is how they are accessing it. Also I just now seen that they have been using a Mac High Sierra as it is a choice under this question asking me which device in regards to. ... I phone 7plus is my phone. It’s an Apple ID question.

[Image Edited by Moderator to Remove Personal Information]