What updates are available to make sure my iPad does not have any viruses

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 at risk. Immunity from malware is a myth perpetuated by those with little understanding of the threat.

There are no AntiVirus Apps available for iOS/iPadOS. Any that claim to provide such protection are “snake oil” - and should be avoided.

The most common risk to which you will likely be exposed are Browser-based attacks can largely be mitigated by installing a good, trusted, 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.

When using a good quality Content blocker, a high proportion of otherwise inescapable risk when using your Safari browser, or linking to external sources from email, is effectively mitigated before it even reaches you.

There are additional protections that can enhance protection further, such as using one of the better Recursive DNS Services in preference to automatic settings. This can either be set on a per-device basis in Settings, or can be set-up on your home Router. I recommend using one of the following filtered DNS services, for which IPv4 ad IPv6 server address are included here:

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, provides defense in depth.

As long as your device is up to date and has not been jailbroken you should be fine.