You can't do it from the iPad. You'll have to go to the website version of your email accounts and do it there. I don't have an account with either of your email providers so I can't give advice on how it works for your accounts.
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There is a search box at the top of the page. Click the arrow there.
A window will appear.
In "From" enter the email address you want to block.
Click "Create filter with this search" at the bottom of this search window.
The next window will open, where you may choose whatever you prefer (one of the options is "Delete").
Then click "Create Filter".
Sign in (on your computer).
Then choose Options - More options. You should find that in the upper right corner.
There you will find "Preventing junk email". Click "Safe and blocked senders".
Choose "Blocked senders".
Write the email address you want to block in "Blocked email address or domain".
Click "Add to list".