Virus message popped up on my iPad

It's a fairly common online advertisement, with a whole pile of utterly false (and impossible) claims. There are no viruses, no hackers, no malware, just an advertisement.

As an example of a bogus claim made by this advertisement, no remote website can run anything as massively invasive as a malware scan. Browser vendors go to substantial efforts to prevent remote websites from accessing and scanning your local storage. If websites could scan your local storage, we'd all be massively breached, our data breached, our passwords breached, our on-device credit card data breached, well, you get the idea. Bad.

These advertisements are usually selling some sketchy and unnecessary security products, and it's the add-on "security" or "privacy" products that can then tend to cause security and privacy issues. Because once installed, these apps have more access to your data, while providing negligible or no benefits over the built-in Apple anti-malware.

The built-in Apple anti-malware can scan your iPhone contents. Add on VPN clients and add-on security clients still can't scan your storage, but they can scan and log more of your activities.

One of the better-known anti-malware packages around for Apple macOS platforms was reselling personally-identified browsing and purchasing data. The security and stability and privacy of these add-ons are not without... concerns.

Here is how to: Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

PS: One other clue that a message is probably a scam? The URL. Apple uses Apple.Com for their communications.

Expanding upon comments of others…

You have encountered a scam warning. Most alerts of this type are designed to scare the unwary into giving away sensitive information - or to fool you into doing something that you shouldn’t. Do not click or otherwise interact with the page. Simply close the browser tab.

There are no AntiVirus scanning products for iOS/iPadOS. Due to the sandboxed security architecture, an AV process is unable to scan the filesystem.

Providing your iPad has been kept up-to-date with system software updates, you should not be concerned for your iPad being directly compromised. Due to the system architecture of iOS/iPadOS, unless jailbroken, your iPad is not susceptible to traditional malware infection per-se. However, as with all computer systems, there are still vulnerabilities and exploits to which you remain vulnerable. Regardless of the installed version of iPadOS, there are useful mitigations that can be used to significantly reduce your exposure to risk.

The majority of threats to which you will be invariably exposed will surface via web pages or embedded links within email. These browser-based attacks can be largely and successfully mitigated by installing a good Content and Ad-blocking product. One of the very best and most respected within the Apple App Store - designed for iPad, iPhone and Mac - is 1Blocker for Safari.

https://apps.apple.com/gb/app/1blocker-for-safari/id1365531024

1Blocker is highly configurable - and crucially does not rely upon an external proxy-service of dubious provenance, often utilised by so-called AntiVirus products intended for iOS/iPadOS. Instead, all processing by 1Blocker takes place on your device - and contrary to expectations, Safari will run faster and more efficiently.

Unwanted content is not simply filtered after download (a technique used by basic/inferior products), but instead undesirable embedded content blocked form download. A further benefit on metered services, such as cellular connections where you data may be capped or chargeable, this not only improves speed but also saves you money. 1Blocker has also recently introduced its new “Firewall” functions - that are explicitly designed to block “trackers”. Being implemented at the network-layer, this additional protection works across all Apps. Recent updates to 1Blocker has introduced additional network extensions, extending protection to other Apps.

A further measure to improve protection is to use a security focussed DNS Service in preference to automatic DNS settings. This can either be set on a per-device basis in Settings, or can be set-up on your home Router - and in so doing extends the benefit of this specific protection to other devices on your local network. I recommend using one of the following DNS services - for which IPv4 and IPv6 server addresses are listed:

Quad9 (recommended)

9.9.9.9

149.112.112.112

2620:fe::fe

2620:fe::9

OpenDNS

208.67.222.222

208.67.220.220

2620:0:ccc::2

2620:0:ccd::2

Cloudflare

1.1.1.1

1.0.0.1

2606:4700:4700::1111

2606:4700:4700::1001

Use of the above DNS services will help to shield you from “known bad” websites and URLs - and when used alongside 1Blocker, or other Content Blocker provides defense in depth.

There are advanced techniques to further “harden” iOS/iPadOS (such as using DoH, DoT and DNSSEC). Apple has recently introduced its new Private Relay to its iCloud+ subscribers - in part employing ODoH (a variant of DoH) as an element of this new functionality.

I hope this reassurance and guidance proves to be helpful in resolving and/or avoiding issues with malicious websites.

You were right to ignore it. That is a FAKE message. Note the web address in the URL window. That is NOT an Apple address.

No one, not even Apple, can tell what is on your computer unless you give permission for remote access. And not iPad can get malware unless you substantially and deliberately modify your iPad.

Do Settings > Safari and scroll down to find "Clear History and Website Data." Make it so, and the should manage that mischief.