What is a Activision account for modern warfare?

Managing Your Activision Account

So I just got warzone, and I need to create an Activision account, as this is the first time it's required. I try to enter in my information, but it says invalid

How to make your Activision account data publicly available

So people are now able to steal activision accounts, you've been warned! : r/modernwarfare

How to Link Your Activision Account to Steam !

How to Link Activision Account Call of Duty Modern Warfare 3 (MW3)｜Game8

Error Connecting to Activision Account: 5 Ways to Fix It

Warzone Mobile Stuck On Logging In To Activision Account Fix - GINX TV

CALL DUTY. WARZONE MODERN WARFARE. Registering for Activision Account Anyone know why I get stuck on

Call Of Duty Accounts Hacked? Activision Denies Any Compromise