You can use the following method:
1. Login to Windows Live Account.
2. Navigate to Bing Master Center.
3. Add your website to Bing search engine by filling the URL bar with your sitemap’s
URL. Afterwards, press Add Site.
4. Bing staff will check and validate the sitemap and the site. They will begin indexing
the site whenever they determine that the sitemap is errorless.
Or you can also use following link:
https://www.bing.com/toolbox/submit-site-url