I bought 2 second hand Iphones, Iphone 6s plus and Iphone SE and it is activation locked and i don't know what to do

What to do?

Return the phones for a refund.

The phones are useless to you unless you can locate the original owner and ask them to release the lock on the phones. It is extremely unlikely that the person who sold you the phones is the original owner.

You will need the original owner to take the locks off. If you purchased from a stranger and through an online marketplace check their policy. You may be able to request a refund if they refuse to remove the lock. Also if you paid via PayPal you would have the same protections. Otherwise…you’re stuck with phones you won’t be able to use.

Return them for a refund.

Either get your money back or toss them in the recycle bin.

They are useless to you.