How do I block people from sending me emails on yahoo and gmail?

[Goldname]

Also, how do I permanently keep all mail from a specific sender to always appear in my spam box? For example, I sometimes want ads to keep me up to date on some specific products, but I don't want it to appear in my actual email box. Thanks.

[Lainie]

As the mail enters your inbox, move it to spam. In a few days it will go directly to your spam folder.

If the sender is in your contact/address book, you will have to go into it and delete them as a contact, and then send their messages to spam when it comes in. In some cases, after you delete a contact, it will automatically go to spam.