# Apps

> What an app is, the four apps Continual ships, and how they share one record of your business.

An app holds the [records](/docs/concepts/records) for one part of your business, with the Actions
that change them. Each app below has a page that explains what it is for, how its work moves, and
every record it keeps.

<Cards>
  <SpectrumCard title="Sales" href="/docs/apps/sales" art="ember">
    Deals from lead to won, the quotes that price them, and the orders customers
    agree to.
  </SpectrumCard>
  <SpectrumCard title="Finance" href="/docs/apps/finance" art="tide">
    Invoices, payments, customer and vendor accounts, and the general ledger.
  </SpectrumCard>
  <SpectrumCard title="Projects" href="/docs/apps/projects" art="grove">
    Projects, tasks, and dependencies, scheduled on the critical path, plus
    synced GitHub work.
  </SpectrumCard>
  <SpectrumCard title="Inbox" href="/docs/apps/inbox" art="sky">
    Your Gmail conversations, synced into private records.
  </SpectrumCard>
</Cards>

## What an app holds

An app defines record types, such as a deal or an invoice. Each record type is one of two kinds:

- An **Object** changes freely, and its history keeps the old values. A deal and a task are Objects.
- A **Document** is a draft until its own Action finalizes it, such as **Issue invoice**. After that
  it is final, and only its own Actions change it, such as **Void invoice**. Quotes, orders,
  invoices, payments, and journal entries are Documents.

Records post entries to ledgers. A ledger is a running tally that is only added to, such as
Finance's general ledger or the count of deals by status. An app's [metrics](/docs/concepts/metrics)
are sums of its ledgers.

An app can also give Continual skills, which say how to do its kind of work. Some apps watch their
records and keep fields up to date, such as a deal's **Ready** and **Overdue** marks or a task's
scheduled dates. A field Continual keeps is marked **set by Continual** in each app's reference.

## How apps share records

Apps meet through records every organization has, whichever apps it installs:

- **Companies and people.** A deal's customer, a quote's customer, and a Finance customer account
  all point to the same company or person. Email in Inbox is linked to the people it was between
  and their companies.
- **Products.** A quote, order, or invoice line can name one of your products.
- **Legal entities.** A quote or order names the entity that sells. Invoices and payments belong to
  an entity, and post to that entity's books.

One record serves every app, so a company's page shows its deals, its invoices, and its email in one
[Activity](/docs/concepts/activity). An order is also something another app can bill: Finance drafts
an invoice from a confirmed order and copies its lines. Sales does not need Finance to work, and
Finance does not need Sales.

## Choose which apps you install

An administrator installs and uninstalls apps in **Settings › Apps**. Installing an app shows its
records, pages, and tools to the organization, and gives you the roles it defines, such as
Finance's **Accountant**.

Uninstalling Sales, Finance, or Projects hides its records, pages, and tools from everyone. Its data
is kept, so installing it again brings everything back. Inbox is **Always installed**, and so is
Agent, which holds your [threads](/docs/concepts/threads) with Continual.

## Next steps

<Cards>
  <Card title="Sales" href="/docs/apps/sales" icon="handshake">
    Start with the pipeline: deals, quotes, and orders.
  </Card>
  <Card title="Records" href="/docs/concepts/records" icon="list">
    How records, their history, and their Actions work.
  </Card>
  <Card title="Record types" href="/docs/developers/record-types" icon="book">
    Every record type in one reference.
  </Card>
</Cards>