There are multiple ways to access bash documentation, one of the most common way on Linux system are the man and info commands. The man and info commands give you the Bash(1) man page. It’s about 100 printed pages.
Below “man bash” command output.
Below “info bash” command output.
You can also checkout the documentation using web here: https://www.gnu.org/savannah-checkouts/gnu/bash/manual/bash.html