> ## Documentation Index
> Fetch the complete documentation index at: https://developer.folk.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

In this section, we will introduce the core concepts of folk's API and how they are used to model the data in your workspace.

## Entities

folk data model is based on two main entities, often also called *contacts*: **people** and **companies**.

<CardGroup cols={2}>
  <Card title="People" icon="user" href="/core-concepts/people">
    A person is a human being that can be associated with one or more companies.

    <br />

    Read more about people <Icon icon="arrow-right" />
  </Card>

  <Card title="Companies" icon="building" href="/core-concepts/companies">
    A company is a business entity that can include one or more people.

    <br />

    Read more about companies <Icon icon="arrow-right" />
  </Card>
</CardGroup>

Depending on your business needs, you might use mostly people or companies, or a combination of the two.

## Groups

folk CRM is built to help you manage specific workflows for your relationships, such as prospecting, pipeline management and keeping track of existing clients.

To map out these workflows, folk uses groups. A group is a database made up of contacts (people & companies). They work as categories to organize different type of contacts to leverage them in different workflows.

A person/company can belong to multiple groups.

<Card horizontal title="Groups" icon="users-viewfinder" href="/core-concepts/groups">
  Read more about groups <Icon icon="arrow-right" />
</Card>

## Custom fields

Every business has different data needs, and folk is designed to be flexible in supporting any kind of data model.<br />
In each group you can define custom fields, which are custom attributes that can be added to people and companies.

<Card horizontal title="Custom fields" icon="rectangle-list" href="/core-concepts/custom-fields">
  Read more about custom fields <Icon icon="arrow-right" />
</Card>