There are no true Antivirus Products available for iOS/iPadOS. Those that claim to provide AV protection are little more than “snake oil” - and should generally be avoided. As for checking for Spam, that’ll be you and your own due diligence when reviewing messages and email:
Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support
However, there is one potential source of issues with your iPad that you may need to manually check - this being for a vulnerability that is often exploited that gives the appearance of a malware infection. This involves your iPad/iPhone Calendar - the symptom being your Calendar appearing to have been populated with regular events that warn of malware infection, or give the appearance of recurrent spam messaging.
Calendar Infection
Whilst not a malware infection in the traditional sense, if this exploit is observed on your device, it is highly probable that you were manipulated (via a simple click on a website link) into “subscribing” an additional (unwanted) Calendar to your device - and this unexpected Calendar is exposing unwanted calendar events and sending you unexpected “adverts” or other warnings.
If you see this issue, you’ll need to check for what’s out of place...
iOS/iPadOS13 and earlier: Settings > Passwords and Accounts
iOS/iPadOS14: Settings > Calendar > Accounts
Look for an “account” that shouldn’t be in the list of accounts - as this will likely include the Calendar that contains all the unwanted events. When/if you find the suspect account, tap - then select Delete Account. This should resolve this specific problem in its entirety.
Malware
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 many vulnerabilities and exploits to which you remain vulnerable. For older devices, no longer benefiting from regular security updates, the risk of an unpatched vulnerability being exploited increases.
Be wary of the often repeated myth that Apple devices are immune to malware; those that perpetuate this fallacy, perhaps with good intention, do not necessarily comprehend the broader threat landscape. Consider that if the myth (and over-generalisation) were true, Apple would not expend considerable resources, as they do, in developing and issuing regular software security updates and patches for its products.
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 largely be 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. All processing 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. 1Blocker has also introduced additional network extensions, extending protection to other network aware Apps that are installed on your iPad.
A further measure to improve protection against threats and exploits 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+APNIC
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 DoH as an element of this new functionality.
I hope this information and insight proves to be helpful.
