Users were only able to submit up to 10 URLs per day and 50 URLs a month before. The monthly quota has been removed, and the daily limit has been increased by 1000x
Major announcement today for the SEO world! Get your content indexed fast by now submitting up to 10,000 URLs per day to Bing https://t.co/XbwxaGfgVr Let’s move away from crawling to discover content change to tell us. Please adopt and save the world from global crawling warming!
— Fabrice Canel (@facan) January 31, 2019
Log in to Bing Webmaster Tools and access the the Submit URLs feature in the Configure My Site section.