Finally, a conclusion about the importance of using official distributors like txt to avoid scams. Maybe add a note about checking if txt is a legitimate reseller, as some fake sites exist. Also, ensure the .txt file is properly saved and not opened with an image viewer if it's a text document. Wait, if it's a .txt file with the activation key, they need to open it with a text editor like Notepad. Clarify that.

Next, after purchasing, the customer receives a .txt file with the activation key. It's important to highlight that they need to check their spam folder in case the email doesn't show up. Then, the activation process involves logging into their Battle.net account. Wait, actually, does Call of duty use Battle.net or PlayStation/Steam? Hmm, I think for the PC version, it's on Battle.net, while console versions might be on different stores like PlayStation or Xbox. I need to clarify that. Maybe the key is for PC, so Battle.net, or if it's a digital code, it could vary. Maybe the text should specify that the key is specific to PC. That way, the user knows where to redeem it.

Then, steps for activation: opening Battle.net, going to the "Games" section, clicking "Redeem..." and entering the key. Need to be precise about each step so the user doesn't get confused. Also, after activation, the game gets listed in their library, and they can install it. Maybe mention that they need to wait for the download to complete.

Also, security tips: Make sure the website is secure (HTTPS), and avoid phishing attempts. If the email seems suspicious, don't click links. Instead, go to txt's official site through a search engine.