How can I encrypt USB drive so that it would subsequently be readable/writable on any computer that I plug it in? For instance, it should then be possible to easily plug the encrypted USB drive on a Windows or Mac computer, and be able to access the contents without any fuss.
As for the solution to encrypt a USB drive on a cross-platform, I guess a third-party utility is the optimal option, which supports sorts of operating systems. If you plan to encrypt a USB drive on macOS and Windows, iBoysoft BitLocker for Mac is suggested here, which allows you to encrypt USB drive on a Mac without a hitch as your Windows PC supports BitLocker drive encryption.
Take care~
Here's step-by-step tutorial about how to encrypt, password protect external hard drive for both Mac and Windows PC usage.
Soluções para resolver 'BitLocker continua pedindo a chave de recuperação' no arranque do Windows 10/11 em computadores Dell, HP, Lenovo, Samsung, ASUS, etc.
Here is tutorial about how to bypass BitLocker recovery screen asking for BitLocker recovery key on startup Windows 11,10, 8, 7 or Surface.