When you are logged in to your PC *and* you are signed in to AxCrypt – then you (or anyone else with access to your PC) can access your encrypted files on your PC. Which makes sense, since you are you and anyone else who can access the computer as if they are you, are… well.. you from the computers point of view.
If you have a screen saver, or the computer goes to sleep, or your log out of Windows, or you sign out of AxCrypt – you or anyone else with access to your PC will need to know your AxCrypt password in order to decrypt and open your files.
In the case of a file that is stored on OneDrive, in no situation is the file accessible except in it’s encrypted form from your OneDrive account on the web or from another computer.
If, for example, you are working on your PC with a file on OneDrive, and at the same time a hacker managed to access your OneDrive account from their own computer or the web, all files there will always remain encrypted.
Files are only decrypted locally on your PC when you open them with AxCrypt. Never remotely in your cloud storage.