Hello MarkVet75.
Thanks for reaching out to Apple Support Communities. I see that you have some concerns about the security of your iPhone 6, and think that it might be hacked. The security of your iPhone is important and I will be glad to assist. First, anti-virus apps or programs are not recommended to be used in iOS. Built-in security features protect against malware and viruses and help to secure access to personal information and corporate data. Was your iPhone modified as in "jailbreaking"? If so, unauthorized modifications to iOS (also known as "jailbreaking") bypass security features and can cause numerous issues to the hacked iPhone. Please see the following resource for more information on this:
Unauthorized modification of iOS can cause security vulnerabilities, instability, shortened battery life, and other issues
I would recommend checking out this resource for steps to secure your Apple accounts if you think they may have been compromised:
If you think your Apple ID has been compromised
Additionally, the iPhone 6 cannot update iOS beyond 12.4.6. To update beyond the current iOS it will require a newer iPhone. Please the following for more information on iOS 13:
iOS 13 and iPadOS are compatible with these devices
Hope this helps.
Cheers.