When you receive an email manually, remember that it is important that you confirm the id provided as the right one, in order to avoid bounces. This will help you avoid addressing any wrong emails (not existing ones or ones with typos) that will trigger deliverability issues caused by the hard bounces that may occur.
Once you have the right email id. You can upload it to your contacts, lists, and segments. Helping you integrate them with your online system as well. You can generally add them by clicking on the plus button with a human icon at the end of each list.
