There are 2 types of reCaptcha: reCaptcha v2 & Invisible reCaptcha. The keys for each are different. Put the reCaptcha v2 under that title, and Invisble reCaptcha under that title. You will find where to enter the keys in Settings on top right navbar. In Settings scroll down to “Anti-Spam Settings:”.
Other Anti Spam Measures
Besides these, DMP also includes automated anti-spam measures such as catching certain words and phrases that are exclusive to spam, as well as embedded links, code, etc. Submissions that include such criteria are prevented from being sent.
DMP also tracks IP’s and looks for bot behavior and checks IP’s against a database of reported abusive IP addresses.