How did I want to clear all the viruses on my phone

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

You don't have any viruses. You may well be getting spam messages and pop-ups telling you that you have a virus. These are designed to con you into disclosing account details or buying useless software. If you are seeing weird messages in your calendar it means you subscribed to a spam calendar. Go to Settings - Calendar - Accounts and delete any calendar accounts that you don't recognise.