It’s not possible to view the Recently Added section of Facebook in the mobile app. If you’re using a phone or tablet, tap your browser’s menu icon and select Request Desktop Website (or similar) to bring up the same version of the site you’d see if you were browsing on a computer. Your friend might have privacy settings that prevent others from seeing the Recently Added tab, so this may not work for you. [1] X Research source
If you don’t see this tab, that person has not added a friend in the last 3. 5 weeks or they have settings enabled that hide this tab.