Because Yahoo uses Bing Search you only have to submit to Bing to be covered for both. The following is a guide on how to get the Bing to index your site and how to verify your siteand sign up for Bing Webmasters.
The easiest way to submit your site to Bing is just to visit their webmaster page https://www.bing.com/toolbox/submit-site-url and type or paste your URL into the box provided.
You can leave it here save in the knowledge that Bings bots will index your site over time.
If you wish, you can take it one step further you can sign up for a Bing Webmasters account, this gives you insights into how traffic is getting to your site. To do this you need to confirm ownership of your site, there are a few ways to fo this, the easiest way with Create isto add the meta-tag and publish your site. Follow the steps below to do this.
Click through to the next page by clicking on the “Great SIgn me up” link.
Next you just need to click though to add your site, don’t worry about the site map for now.
On the next page, highlight, right click, copy the Meta tag from the first box in option 2 (ignore the code in the example) keep this page open and open a new tab with your Create account.
Log in to your Create account and go to your Content page, click on the setting button for your Home page then go to the Meta Info tab and paste the Meta tag you got from Bing into the Custom <Head>: box on this page. Save and publish your site then go back to your Bing click verify on your
Bing webmasters page.
You are done. Your site is now in your Bing Webmasters account.