How do I block unwanted emails on my iPad?

If your email address is being used as a target for spam or unwanted email, there is little that you can do to stop it; anyone that has your email address can send email to it. Instead you have to “manage” it…

First, be wary of any “unsubscribe” links that may be embedded in the email messages. For the most part, unless the unsolicited email is from a reputable advertiser, the unsubscribe link will not stop the messages. Instead, clicking the link will simply confirm to a spammer that the email address is monitored by a warm-blooded victim - and more spam and unwanted content is likely to come your way.

For unsolicited email, you can use the native blocking feature of iOS/iPadOS to automatically block/delete unwanted email from a sender - although this will only be effective for spam that arrives from a consistent email address:

Block phone numbers, contacts, and emails on your iPhone, iPad, or iPod touch - Apple Support

Where the spam email is using “spoofed” email sender addresses, your block-list will be ineffective.

The best advice is to avoid becoming a victim. Be careful where you use your email address to subscribe to services. Perhaps keep a secondary address just for this purpose - or, if you have updated to iOS/iPadOS15.1 or later, consider using Apple’s new Hide My Email facility:

What is Hide My Email? - Apple Support

Set up and use Hide My Email in iCloud+ on all your devices – Apple Support

Again, this new feature cannot stop everything, but is another way to reduce the likelihood of receiving and managing email and messaging spam.