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

# How field rules work in Cloneable forms

> The six things a rule can control on a template field: when it appears, is required, is editable, what it checks, which options it offers and its value

Every field on a Cloneable template can carry rules. A rule controls one of six things about the field, and each has its own section in the field's settings. The web and the iOS app apply the same rules, also offline.

## The six things a rule controls

| What | Field settings section | Set it as |
| - | - | - |
| **Shown**: whether the field appears | **When it appears** | Always, **Only when…** a condition, or an expression |
| **Required**: whether it must be filled | **When it's required** | The required checkboxes, **Only when…** a condition, or an expression |
| **Editable**: whether crews can change it | **When it's editable** | **Read-only**, or a condition or expression that locks it. See [Lock a field with a rule](https://docs.cloneable.ai/guides/forms/lock-a-field.md) |
| **Check**: whether the value makes sense | **Checks** | An expression and the message crews see when it fails. Checks never block saving |
| **Options**: which values it may hold | **Options** | A list, a custom type's values, or a dataset, optionally filtered by the record. See [Show dropdown options by location](https://docs.cloneable.ai/guides/forms/filter-options-by-location.md) |
| **Value**: filling it from data | **Auto-fill** | Another field, a dataset column or a formula, as **Auto** (always filled) or **Suggest** (one tap to use) |

Start with the simplest setting that does the job. A condition reads as a sentence in the builder. Use an expression only for what a condition can't say.

Every one of these can read the object a record links to. See [Rules that read a linked object](https://docs.cloneable.ai/guides/forms/rules-on-linked-objects.md).

## Guides

> [card] [Link fields](https://docs.cloneable.ai/guides/forms/link-fields.md)
>
> Link a record to another object, or to a list of objects.

> [card] [Rules on linked objects](https://docs.cloneable.ai/guides/forms/rules-on-linked-objects.md)
>
> Show, require, lock, check or fill a field from a linked object.

> [card] [Lock a field](https://docs.cloneable.ai/guides/forms/lock-a-field.md)
>
> Make a field read-only always, or while a rule is true.

> [card] [Options by location](https://docs.cloneable.ai/guides/forms/filter-options-by-location.md)
>
> Offer only the dropdown options that apply where the crew is.


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