# Fields and entry helpers

> The field types Log supports and the helpers that make entry fast and consistent.

Each field on a form has a **type** that decides how you enter it, and may offer
**helpers** that speed up entry and keep data consistent. Both come from your
configuration.

## Field types

| Type | How you enter it |
| --- | --- |
| **Text** | Type a value. |
| **Number** | Enter a number, with the field's units shown. |
| **List** | Choose from a defined list of values. |
| **Unit** | Choose a unit. |
| **Date**, **Time**, **Date and time** | Pick from a calendar or clock, with **Now** and **Clear** shortcuts. |
| **Yes / no** | A simple toggle, with a **Reset**. |
| **Degrees, minutes, seconds** | Enter a coordinate in DMS. |
| **Builder** | Compose a structured description. See [The Builder](/log/logging-data/builder). |

## Required fields

- A **red asterisk** marks a field that is **required** to save the record.
- A **green asterisk** marks a field that is **required on completion** - you can
  save without it, but it must be filled before the location can be marked
  complete. See [Completing a location](/log/logging-data/completing-a-location).

## Visibility

Fields can **show or hide** based on your other answers - for example, blow counts
that only appear for certain sample types. This keeps each form to just the
fields that apply, so you are not scrolling past ones you do not need.

## Defaults

A field can carry a **default value** that fills in for you. Some defaults
**refresh as you enter data**, recalculating from what you have typed - useful for
running references and derived values.

## Previous value

Many fields offer a **previous value** helper - reuse the value from your last
record for that field. Combined with [Create more](/log/logging-data/records#create-more),
it makes logging a run of similar records quick: keep what is the same, change
only what differs.

## Autofill

Some fields **autofill from a selection** - choose a probe type or hammer, say,
and related fields populate automatically from your configuration, so you enter a
value once instead of several times.