[Feature]: Add @return and @examples to all the functions in the project

[DouglasMesquita]

Guidelines

• I agree to follow this project's Contributing Guidelines.

Description

Currently, none of the functions are presenting @return and @examples. It is highly recommended to have it in order to submit it to CRAN.

Problem

CRAN acceptance will become easier.

Proposed Solution

Add @return and @examples in all functions in the package.

Alternatives Considered

No