What is the ruling on working as a sales representative for a company that sells clothes, some of which are modest and some immodest, given that immodest clothes are displayed in the catalog or on the website? And do I bear a sin for this, and how can I expiate it?

Scandalous clothing is not permissible for a woman if she adorns herself with it [for display], but it is permissible for her husband. Selling such clothing is permissible as long as it is not known or highly probable that it will be used for unlawful purposes, especially if such use is prevalent in the country. Displaying these clothes on images of adorned women is permissible only among women, provided their 'awrah is not visible. However, displaying them in a way that men can see is not permissible. The questioner's work in the company is permissible if her role is limited to what is lawful; otherwise, she must leave it and repent.