How can I delete excess emails in my yahoo account?

On my Galaxy S6 I am getting the message to delete some files so there is room available for more emails to download. What are the steps to do this correctly? I have tried several different pathways to delete files and all the emails are still there blocking the download of my current incoming emails.

from Android Forums at AndroidCentral.com - Ask a Question http://ift.tt/29qtC6k
via IFTTT