babel package : http://mirrors.ctan.org/macros/latex/contrib/babel-contrib/azerbaijani/azerbaijani.pdf
Download this file : https://gitlab.com/a10684/auto-multiple-choice/-/blob/master/I18N/auto-multiple-choice.pot?ref_type=heads
Translate et send the file to Alexis Bienvenüe.

I wasnt able to handle this way that you suggest, so I did it like that,

\newunicodechar{Ə}{\textazeriSchwa}
\newunicodechar{ə}{\textazerischwa}

\DeclareRobustCommand{\textazerischwa}{%
  {\fontencoding{T2A}\selectfont\symbol{"BA}}%
}

\DeclareRobustCommand{\textazeriSchwa}{%
  {\fontencoding{T2A}\selectfont\symbol{"9A}}%
}

so actually it works for me, the main problem is when I insert images and want to add width, it shows width as a text, and not showing an image

Could you post a MWE ?

preamble
\usepackage{MWE} <-important
your commands \newunicode
\begin{document}
dummy text

\includegraphics[options]{example-image}

\end{document}