I have been getting messages from 844-926-***3 regarding a breach. Seems suspicious

iOS / iPadOS devices cannot be hacked or infected with Virus / Malware / Spyware if it is updated to the latest iOS/iPadOS unless you have intentionally downloaded spurious software or unauthorized apps directly from the internet and installed on your device or/and have Jail Broken. 

It (Hacking) also depends on how careful are you in sharing sensitive and valuable information pertaining to your iPhone such as Passcode, Password etc with your friends and family members.

Be careful when sharing the device's sensitive and valuable information with friends and family members.

Thumb Rules:

1. Enable  Guided Access before handing over an iPhone to kids
2. Don't share Apple IDs
3. Don't Jail Break
4. Don't share sensitive information pertaining to your device and payment methods
5. Beware of Phishing

And Apple will never call you unless you have set up a Support call. In the event that they do discover a security problem with your account they won't call you, they will lock it and wait for you to find out and contact them. That way you can be sure who you are talking to.

Any phone call, email or text message claiming to have detected viruses on your device, or a breach in your iCloud account, is fake.