How Secure Are Encrypted Files/folders?

Let's say I want to encrypt/protect some of my files/folders so that NOBODY
can access it except me, does such a thing exist or is every encryption software
pretty much accessible/hackable by any expert who has the time and resources to crack it?

 

well, you probably answered your own question.
it would all depend on how eager they were to see what you have encrypted.
https://www.2brightsparks.com/onclick/index.html
EncryptOnClick works pretty well. [ and freeware ]
not a bad idea now-a-days.

 

You can use a compression tool like winzip or 7zip and you can encrypt that with a password