Short answer: Custom fields are how a task list becomes something you can report from, bill against, and forecast with. Most agencies either use none — losing every dimension that matters — or configure twenty and fill in four. The discipline is simple: a field earns its place only if it changes a decision or appears in a report. Six fields cover almost all agency delivery.
The six that pay for themselves
1. Billable — toggle
Whether the work is chargeable. Decided at task creation, not at invoicing. Deciding at invoice time means deciding under pressure to hit a number; deciding upfront makes the invoice a report rather than a construction.
2. Deliverable Type — dropdown
Design, copy, development, strategy, admin. This is what lets you answer "what does this client actually consume?" — which is the foundation of pricing a renewal correctly.
3. Client Visible — toggle
Whether this task should ever appear to the client. Useful even if you don't currently share anything, because it forces the question at creation time and gives you a filter the day you do.
4. Approval Required — toggle
Whether the deliverable needs client sign-off before it counts as done. Without it, "done" is a matter of opinion and finished work gets reopened weeks later.
5. Effort — dropdown or number
A rough size, not an estimate in hours. S/M/L is enough. Its job is capacity planning, and simple scales get filled in while precise ones don't.
6. Request Source — dropdown
Where the work came from: contracted scope, client request, internal initiative, change order. This is the field that makes scope creep visible. If a growing share of a client's work is tagged "client request" and no change orders exist, you've found your margin leak.
What to skip
Priority, unless it's actually enforced. Most agency priority fields end up with everything on High.
Duplicate ownership fields. Assignees already exist. A second "Owner" field creates two answers to one question.
Percent complete. Self-reported, rarely accurate, and statuses already tell you more.
Internal rates or margins on client-visible tasks. Custom field values render inside the task — if a client can open it, they can read the field.
One security note: everything inside a shared location is visible to whoever it's shared with, custom fields included. If you're using guest access, any field holding cost, margin or account-health data is exposed the moment that List is shared.
Where to define them
Define fields at the Space level so every client Folder inherits them. Defining per-List means twenty slightly different versions of "Deliverable Type" and no ability to report across clients.
Then put them in your client template. If a new client Folder arrives without the fields already in place, they won't be added retroactively.
Frequently asked questions
What custom fields should agencies use in ClickUp?
Billable, Deliverable Type, Client Visible, Approval Required, Effort, and Request Source. Between them they cover billing, reporting, capacity and scope tracking. Add anything beyond these only if it changes a decision.
Where should custom fields be defined?
At the Space level, so every client Folder inherits the same set. Per-List definitions produce inconsistent variants and make cross-client reporting impossible.
Can clients see ClickUp custom fields?
Yes, if they have access to the task. Field values render inside the task detail, so anything internal — rates, margins, account notes — is visible to anyone the location is shared with.
How do I track scope creep in ClickUp?
A Request Source field distinguishing contracted scope from ad-hoc client requests. Filter by client and look at the ratio. A rising share of unplanned requests without matching change orders is scope creep with a number attached.
The short version
Six fields, defined at Space level, baked into your client template. Each one has to change a decision or appear in a report. Request Source is the one most agencies don't have and most need, because it turns scope creep from a feeling into a figure.
Just keep anything sensitive out of fields on tasks clients can reach. See how to show clients progress without exposing the workspace — 7 days for $1.