I think that you should have a report a user button to report people who use Yahoo for fraudulent purposes.
Yes, people have asked for a report button but here is my take on it.
Spam is spam and we can just click it and it goes to the spam bin.
Scammers are sending "lottery winnings, loan scams and move funds out of Africa scams" using your platform.
Most of us are savvy and do not fall for this but there are people who do lose their hard-earned savings because of them.
You should have a big red button on Yahoo mail that is visible to all. The scammers who send the mail should also know that you will send the link of their email to Yahoo. I have just received an email with the "move millions from Africa" scam and the email address showed something else but when you click the reply button, the sender is using a Yahoo email address. I should be able to report spammers as well as scammers and phishers to you when they use your mail for fraud.
Hi there!
If you see content on Yahoo that violates the Terms of Service, let us know right away.
In many cases, you can report inappropriate content directly from our products. In Yahoo Mail, you can click Spam from the email in question and select a reason.
If a Yahoo Mail account is sending you spam, you can report it to Yahoo directly. Here’s how:
https://help.yahoo.com/kb/report-abuse-spam-yahoo-sln26401.html
Hope this helps!