help to fix the verification code

Hi I've bought an iPhone X from someone else, and i cannot use it because the apple id which has been used before, is not the one that is shown on the iPhone screen! how can i find the correct apple id and its password?

I tried to erase the last device on "find my iphone" but i found nothing. I also checked my apple id list to find any info, but again nothing. when i turn on my device, it asks my apple id and password with a hidden mail, but the problem is that the mentioned id is not familiar for me and the previous owner. could you help me finding a solution please?