If you want to close a Mylife account, you can easily do that in the Settings page of your account.
I’ll show you below with pictures how I managed to remove my profile (using a desktop computer):
1 Login to your account on mylife.com
and click on your name initials in the upper right corner. Then select My account.
2 Choose Deactivate account (in the menu on the left side).
3 Confirm that you want to remove your profile
and don’t be distracted by the orange Control your identity button.
Your account will be deleted immediately and permanently.
Source screenshots (and thanks to): mylife.com