How does partitions work in Android? Can they be modified safely?

I understand how partitions work on a hard disk, also how to use programs to create, change, and delete these partitions. I am also using Android for quite some time. In this question, I would like to focus on the Android partitions only. I found [CyanogenMod Wiki - Common Partitions and directories](https://web.archive.org/web/20161225045502/https://wiki.cyanogenmod.org/w/Doc:_more_concepts#Partitions_and_directories) (archived). But I would like to understand a little bit more: - Is the concept similar to hard disks? - Can these partitions also be changed? Or would it be necessary at all? - Are there tools to change the partitions? - Can I brick my device forever when working on the partitions?