Virus scan for iPhone required by bank

What documentation or reviews Apple might offer, you will have to ask them.

More generally, your bank is running a checklist intended to reduce their exposure. If it culminates with “install anti-virus” for an iPhone or iPad, probably also not providing the best security advice.

Your iPhone already has anti-malware, built in. All do. The app store and related are part of that, too. (That built-in security also blocks add-on anti-malware from scanning the data contents of an iPhone. The add-ons are left to connect into your network traffic.)

More interesting will be migrating to a password manager such as the built-in iCloud Keychain, as that makes getting phished much tougher.

Also migrating the bank login to two-factor authentication, as that also makes getting breached tougher.

Same for enabling two-factor on your Apple Account, too.

You will want to move to unique and robust passwords too, as re-using passwords is doom.

Got concerns about what apps are installed? Factory reset, and don’t restore a backup.

Related: Better Securing Your Data, and Apple Account - Apple Community

But again, for what Apple might offer, you’ll need to discuss that with them.

PS1: Why use password managers? Password managers will automatically fill in the correct passwords, but that fill only happens on the actual website, and not on phishing websites. If the password doesn’t auto-fill for a website, some caution is warranted.

PS2: The bank should really have passkeys available, as those can’t be entered on other websites, and are more difficult to compromise, and can’t be re-used on other websites; the equivalent of no password re-use with passkeys. Basically, passkeys can’t be phished.