How to apply patches on OpenBSD system/kernel and packages easily

Originally published at: https://www.cyberciti.biz/faq/howto-apply-updates-on-openbsd-operating-system/

I am a regular Linux system user. In Linux (especially CentOS), I am used to applying updates a few times a week using , but how do I do that on my OpenBSD severer? How do I apply updates on OpenBSD operating system?