So I got a iPhone 6s but it has a activation lock and the previous owner doesn’t remember their iCloud or their password how do I get pass it
How do I get rid of the activation Lock with out the information to the iCloud
You can't unless the previous owner recovers their ID/password and signs out. Have them try the links below.
Apple ID - How to find your Apple An iCloud e-mail address is an Apple ID.
Enter their Apple (iCloud) ID and click Forgot Password.