latexindent is a perl script that can help you format LaTeX files. It is shipped with texlive (at least 2020 version). To use it you have to install some other perl packages.
@@colbox-blue Warning!! Don’t try to install latexindent in a conda environment. It does not work at the moment of writing. Some perl packages cannot be installed. @@
Step 1. Install perl
sudo apt install perl
Step 2. Install the perl package management tool cpanm.
sudo cpan -i App::cpanminus
Step 3. Install the needed perl packages
sudo cpanm YAML::Tiny sudo cpanm File::HomeDir sudo cpanm Unicode::GCString sudo cpanm Log::Log4perl sudo cpanm Log::Dispatch::File
Step 4. If everything worked, you should be able to see the help information of latexindent by