Custom Fields (UDFs) in Law App: A Guide for Document Writers

Custom fields (UDFs) let your firm capture information Law App doesn’t have a built-in field for, and merge it straight into your templates. There are two kinds, they’re numbered separately, and every number is permanent once it’s saved — which is the part that trips people up most.

The two kinds of custom field

Firm-wide fields and one-off fields never interfere with each other. Someone adding a one-off field to their own matter can never change what [UDF_3] means in your template.

Firm-wide

Set up once, used everywhere

Created in Settings and applied to whichever file types you choose. Appears on every matter of those types. In a template: [UDF_1], [UDF_2] and so on.

On this file only

Added to a single matter

Created directly on one matter and exists nowhere else. In a template: [FILEUDF_1], [FILEUDF_2] and so on.

How custom field numbers work

The number in [UDF_3] belongs to that field for life. It’s assigned the moment the field is first saved, it never changes, and it’s never handed to another field afterwards — even if fields are reordered, added or archived.

A number always means the same field, on every matter type it’s assigned to. On a matter where that field doesn’t apply, it simply merges blank — so one template can safely serve several areas of law at once.

Don’t assume by position. The first field shown on a matter isn’t necessarily [UDF_1]. Always read the number from the Merge field column in Settings, not from the order fields appear on the matter screen.

Adding a firm-wide custom field

Go to Settings, then File Setup, then Custom Fields.
Click Add and fill in the row — see the field-by-field breakdown below.
Click Save. The Merge field column fills in — that’s the number to use in your templates, and the only place you need to look it up.

What each column means

# — display order on the matter screen only. Pre-filled for you; changing it later is always safe.
Reference — which file types the field applies to. Tick as many as you need, or tick All.
Field Name — required; the internal name.
Merge field — read-only. Blank until you save, then shows the token to type in templates, e.g. [UDF_3].
Archived — ticked when a field has been removed. Archived fields sit at the bottom of the list; untick and save to bring one back.
Type — Text, Number, Date or Checkbox. A Checkbox shows on the matter as a Yes / No switch.
Display Label — what the user sees on the matter. Leave blank to reuse the field name.

Settings, File Setup, Custom Fields screen listing firm-wide fields with their # display order, Reference file types, Field Name, read-only Merge field token, Archived tickbox, Type and Display Label columns.

Adding a field to one matter only

Open the matter, go to Details, and scroll to the UDF section.
Click Add field in that section header.
Give it a name, a type, and an optional label.

It appears straight away as an input in the UDF section, ready for a value.

The UDF section on a matter showing custom field inputs — including Early Bird, Key Date, Global Field, Referral Source, estimatedValue and an Urgent Yes/No toggle — with the Add field link in the section header.

The same Add field dialog lists every one-off field already on the matter, with its number — for example [FILEUDF_2]. A field you’ve just added shows “number assigned on save” until you save the matter.

The Add field dialog on a matter, listing one-off fields already on the file with their FILEUDF numbers, and an Archived on this file section with a restore option.

Removing a custom field

Removing a field — whether in Settings or in the Add field dialog on a matter — archives it rather than deleting it. You’re asked to confirm, and the confirmation names the merge field so you can check no template still relies on it.

The confirmation dialog shown before archiving a custom field, naming the merge field and explaining that templates using it will merge blank from then on and its number won't be reused.

Archived fields disappear from the matter, but their number is retired with them and the values already entered are kept. A template that still uses the number simply merges blank instead of picking up a different field.

Archived by mistake? In Settings, the field is still listed at the bottom with Archived ticked — untick it and save. On a matter, the Add field dialog lists archived one-off fields under “Archived on this file” with a restore button. The field comes back with the same number and the values it had.

Working out a field’s number

Firm-wide: Settings, File Setup, Custom Fields — read the Merge field column. Don’t count fields on the matter screen: that order is display order and can differ, and fields from other file types aren’t shown there at all.
One-off: open the matter, click Add field, and read the number next to the field in the list.

Shortcut: the merge field picker in the Word add-in also lists UDF 1–10 and File UDF 1–10. Higher numbers still work — just type them by hand.

Merge field syntax

Inserting a value

Insert a value{{[UDF_1]}}

Dates

Long form{{[UDF_3@d MMMM yyyy]}}
Short form{{[UDF_3@dd/MM/yy]}}

Money

With a dollar sign{{[UDF_4-$amount]}}
Without a dollar sign{{[UDF_4-amount]}}

One-off fields work the same way. Just swap the token, e.g. {{[FILEUDF_1@d MMMM yyyy]}}.

Showing a sentence only when a tick box is ticked

{{IF (([UDF_2])) EQUALS ((Yes)) DO ((This matter has been marked urgent.))}}

Choosing between two wordings

{{IF (([UDF_2])) EQUALS ((Yes)) DO ((We will prioritise this matter.)) ELSE DO ((We will attend to this matter in the usual course.))}}

Keeping or dropping a whole block of formatted text

This is the right tool for a clause or a signature block, where the wording itself needs its own formatting:

{{FORMATTED IF (([UDF_2])) EQUALS ((Yes)) DO ((FORMATTED Result 1)) ELSE DO ((FORMATTED Result 2))}}

Then mark the two blocks with ((Result 1)) and ((End Result 1)), and ((Result 2)) and ((End Result 2)). The losing block and all four markers are removed when the document merges.

Things that catch people out

Comparisons are case sensitive. EQUALS ((Google)) matches; EQUALS ((google)) does not.

Checkbox fields merge as Yes or No, never “true”. A Checkbox shows on the matter as a Yes / No switch, so always compare against ((Yes)).

Don’t assume by position. The first field shown on a matter isn’t necessarily [UDF_1] — always read the number from Settings.

Greater than / less than only work on dates and numbers. Pointing one at a text or tick box field puts an error message in the document.

A number with no field behind it, or with an archived field behind it, merges blank rather than failing — so a template is safe to use on matters that haven’t filled everything in.

A date format aimed at a text or tick box field is simply ignored — nothing breaks if it’s pointed at the wrong field type.