> ## Documentation Index
> Fetch the complete documentation index at: https://docs.conversion.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Fields
> Create and manage the fields on each object in your Conversion workspace, and link them to fields in Salesforce.
Fields are the properties stored on each record of an object. Open **Settings → Objects**, choose an object, and open its **Fields** tab to manage them. The same field manager appears on the **Fields** and **Member fields** tabs of the [Campaigns](/product-docs/workspace-settings/campaigns/overview) settings page, for campaigns and campaign members.
## The fields list
Fields are listed alphabetically by label. Each row shows:
| Column | Description |
| ------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Icon | The field's data type. |
| Label and key | The display name and the key used in Liquid and the API. Hover over the label for details such as the type, fill rate, and number of distinct values. |
| Type | **String**, **Number**, **Boolean**, **Date**, or **Date and time**. Relationship fields show the related object, or *N objects* when they can point at several. |
| Fill rate | The percentage of records that have a value for this field. Not shown for campaign members. |
Use the search box to filter by label or key. Open **Filters** to narrow the list further:
| Filter | Options |
| --------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Owner** | **All owners**, **Custom** (fields you created), **Conversion** (built-in fields whose values Conversion writes), or **Salesforce** (built-in fields whose values come from Salesforce). |
| **Hide empty fields** | Hides fields that no record has a value for. Not available for campaign members. |
## Creating a field
Click **New** and fill in:
| Field | Description |
| --------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Type** | **String**, **Number**, **Boolean**, **Date**, **Date and time**, or **Relationship**. |
| **Label** | The display name. |
| **Name** | The key, generated from the label. Lowercase letters, numbers, and underscores only, and it must be unique on the object. It can't be changed after creation. |
Click **Create**.
New fields can't be added to Opportunities from this page. You can still link existing opportunity fields to Salesforce by editing them.
### Relationship fields
A relationship field lets each record link to one related record, for example each contact to a project. Relationship fields can be created on contacts, companies, and custom objects in workspaces with custom objects enabled.
Under **Relationships**, click **+** (**Add relationship**) and choose the related **Object**: contacts, companies, opportunities, or a custom object. Give that side a **Label** and **Name**; the label defaults to the plural name of the object you're creating the field on. Add more objects to let a single field point at a record on any of them.
The value lives on the object you're creating the field on. Each related object gets a matching field that lists the records pointing at it.
## Editing a field
Click **Edit** in a field's options menu to open the **Update field** panel. A field's type, name, and object can't be changed.
* **Label**: editable for custom fields. Click **Save** to apply the change.
* **Relationships**: for relationship fields, click a related object to rename that side of the relationship.
* **Linked Salesforce fields**: the Salesforce fields this field syncs with (see below). Changes here save on their own.
## Linking fields to Salesforce
Linked fields sync values between Conversion and Salesforce. The **Linked Salesforce fields** section has one row for each Salesforce object the field can be linked to:
| Conversion object | Salesforce objects |
| ----------------- | ----------------------------------- |
| Contact | Contact, Lead |
| Company | Account, Lead |
| Opportunity | Opportunity |
| Campaign | Campaign |
| Campaign member | Campaign member |
| Custom object | The linked Salesforce custom object |
A field can be linked to one Salesforce field per Salesforce object.
Click **Add** on a Salesforce object's row, choose the Salesforce field in the **Link field** dialog, and click **Continue**. For relationship fields, only Salesforce lookup fields that point at the related objects are offered.
Choose how values flow between the two fields: **Prefer Salesforce unless empty**, **Always prefer Salesforce**, **Always prefer Conversion**, **Two-way sync**, or **Do not sync**. Then click **Save**.
Modes the field can't use are disabled, and a warning icon explains why. For example, relationships are read from Salesforce and never written back, and fields Salesforce doesn't allow writes to can only be read.
When you link a field, Conversion may import the field's existing values from Salesforce. Values can take a few minutes to appear.
Once linked, a row shows the Salesforce field and an icon for its sync mode. Click the row to change the sync mode, or click **Remove link** to unlink it. Some links are required or managed by Conversion and can't be removed. Removing a link cannot be undone, but the fields can always be linked again later.
## Deleting a field
Only custom fields can be deleted. Click **Delete** in the field's options menu. The dialog shows how many references the field has; click the count to review them. Type the field's key and click **Confirm and delete**.
Once a field has been deleted, existing references to it are considered invalid, and deleting a field cannot be undone.