How to change junk mail settings in ios

You may also --> Manage junk mail in Mail on iCloud.com - Apple Support (IN)

Report junk mail

On your iPhone, iPad, or iPod touch, swipe left on the message, tap More, then tap Move to Junk. On your Mac, select the message and click the Junk button in the Mail toolbar. Or you can drag the message to the Junk folder in the sidebar.

Report and block spam in iCloud mail - Apple Support (IN)

When you say email, what is on your mind Google, iCloud, AOL, Exchange, Outlook, Yahoo or any Other.