To quickly block an email address as a spam sender, swipe the email and choose the 'Spam' action. This will move the email to the spam folder and also block the sender's email address.
The spam popup screen that then appears usually has a button called 'Block Similar' for more options for blocking similar emails. If this button does not appear then the sender may be using Gmail or Outlook which requires advanced settings to block.
When a spam sender address is blocked, all future emails from that sender address or domain will be moved to the spam folder automatically.

For advanced spam control you can tap on the information button ⓘ when viewing an email or beside an email in the inbox.
There are several sections in that screen help to deal with spam.

Spam Suggestions
The Spam Suggestions section displays quick suggestions on how to block any future emails from this sender. Various options are shown to block this email. You can simply tap on 'Block for Spam' to block the email with the suggested spam option.

The number of matching emails in the inbox and also the spam folder is displayed to help you choose which option is best.

You can change the option before you block the email. Some emails have more advanced options like blocking an IP address network where server farms are used to send spam in bulk. Other options including blocking email address domain suffixes like. eg. .icu, .xyz
More details


Spam Analysis
This section displays a lot of advanced details about the email to help with combatting spam.
You can block emails by the sender address or the sender address domain (@example.com).
For advanced users, the curved arrow buttons to the right of various subjects allow you to create or modify rules based on the subject information displayed.

From Address Suffix
You can also block emails by the the email address domain suffix. This is the last part of the email address. eg. .abc, .autos, .shop etc.
Be aware that there may be some genine emails using the address domain suffix you can block. eg. shop

Sender IP Address
This is the network address of the sender device or email server.
If there are other emails sent from the same network address, then the email totals in each folder will be displayed below the address label.
You can also use the IP address in email rules and filters. View

You can also block emails by IP address or the server network. If there are a lot of emails in your spam folder from the same sender IP address then any future emails from this IP address will be blocked.
Be aware when you block an IP address server network that you may block other servers in this network that are not spam senders.

Location
You can tap on the location button to do a search for the approximate location of an email sender. This can help see where the sender is located.

Spam Status
You can view a summary of the spam checks that were done for this email in the 'Spam Status' section. Tap on this section to view more advanced spam checking information in the spam summary screen.
If an email was checked by the Spam email rule then the Spam Status will appear to show the results of the Spam check. View

The results of the advanced DKIM, DMARC and SPF email tests are shown in this section.


In the bottom of this screen, you can access and edit the various lists that are used to block or allow emails.