> For the complete documentation index, see [llms.txt](https://plus-skill.gitbook.io/plus-skill-whitepaper/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://plus-skill.gitbook.io/plus-skill-whitepaper/systemary/in-app-element.md).

# In-App element

- [Quiz](https://plus-skill.gitbook.io/plus-skill-whitepaper/systemary/in-app-element/quiz.md)
- [Earning](https://plus-skill.gitbook.io/plus-skill-whitepaper/systemary/in-app-element/earning.md)
- [Fee](https://plus-skill.gitbook.io/plus-skill-whitepaper/systemary/in-app-element/fee.md)
- [Credit](https://plus-skill.gitbook.io/plus-skill-whitepaper/systemary/in-app-element/credit.md)
- [Rental system](https://plus-skill.gitbook.io/plus-skill-whitepaper/systemary/in-app-element/rental-system.md)