Ask HN: How do you store your important personal files?

Is there a common way you store important personal digital files, such as 2FA security codes, passwords from very rarely used systems, scans of personal documents? I always have the feeling of getting lost storing these stuff, and losing 2FA auth codes would be terrible for me, so I am trying to scatter them around and email them to my other accounts, but at the same time I think this is not the safest way of doing things as this increases the potential vulnerability surface.

Do you have any service you use or practice you follow for these kinds of long-term storage/file-keeping needs?