There is no single Bash standard to follow, only a few guidelines. One way you can check for some basic errors and formatting would be using an editor with support for Bash (in best case with a builtin LSP). At the end, you have to find your style and coding standards or adapt what others do if you want work with them or edit their files.
Otherwise there is a well known tool for checking Bash files: www.shellcheck.net You can use it online and as a downloaded program on your local machine. After using shellcheck for a bit I got used to some of its conventions and recommendations, such as always wrapping variables like in ${variable} and some other things.
Related is the Bash Reference Manual from GNU: www.gnu.org/software/bash/manual/bash.html Off course this is not a guide on how to style or program, but it helps in understanding how GNU does things.