The quick answer
Go to Customization > Forms > Entry Forms and click Customize next to your customer form (or Edit if it's already a custom form). Give it a name, check Form is Preferred if new customers should open on it, then on Fields > Financial check Mandatory on the Terms row and save. Anyone who creates or edits a customer on that form in the NetSuite UI can't save until Terms has a value. Other forms, imports, and integrations need their own checks.
Sales reps skip Terms when they create customers, and nobody notices until invoices go out with no payment terms. The example fixes that on the form. It copies the Standard Customer Form as AR Customer Form, makes Terms mandatory, sets the form as preferred, and then tries to save a new customer without Terms. The screenshots use sample data and fictional person and operating-company names.
Before you start
You need a role that can customize entry forms. The example uses Administrator. Check that the payment term you want exists under your account's terms list; the example uses Net 30.
Figure out which forms your team actually uses to create customers. If it's already a custom form, edit that one instead of making another copy. Roles can have their own preferred customer form, and users may be able to pick another form from Custom Form. Any form they can use without Terms marked mandatory is a way around this.
The rule belongs to the form. It applies when someone saves a customer on that form in the NetSuite UI. CSV imports, SuiteScript, web services, integrations, and online customer forms may use a different form or validate differently. If every channel has to require Terms, test each one and add a check that runs on the server, such as a User Event script or workflow.
Making Terms mandatory doesn't fill it on customers you already have. Those stay blank until someone updates them, and editing one on this form will ask for Terms before it saves.
01. See the gap
Open an existing customer and select the Financial subtab. In the example, Brookfield Hardware was saved with Terms blank, so invoices for it won't pick up payment terms from the customer. A transaction form, workflow, or user can still set terms on the invoice itself.
02. Customize the customer form
Go to Customization > Forms > Entry Forms. Standard forms show Customize, which creates a custom copy. Custom forms show Edit. Click Customize next to Standard Customer Form.
Replace the default Name with AR Customer Form and check Form is Preferred. A preferred form is the default when someone creates a new customer, unless their role has its own preferred form. Leave Store Form with Record clear unless you want each customer to keep opening on the form it was created with. With it clear, a saved customer opens on the viewer's preferred form.
03. Make Terms mandatory
Open the Fields subtab, then the Financial tab inside it. On the standard customer form, Terms sits there in the Account Information field group. If your form has been rearranged, find the Terms row wherever it is. Check Mandatory and leave Show checked. If you hide a mandatory field, nobody can fill it in, and the form can't be saved unless something else sets the value.
Click Save. Back on the Entry Forms list, AR Customer Form appears with Edit and a checked Preferred box. In this example, Customer Form - Sales had been preferred and no longer is. Your list may show a different form losing the checkbox.
04. Try to save without Terms
Go to Lists > Relationships > Customers > New. Custom Form should show AR Customer Form. If it shows another form, check whether your role has a preferred form of its own or whether the form is available to your role. Enter Granite Bay Supply as Company Name. Primary Subsidiary is already filled in this example; in a OneWorld account, check it before saving. Your account may require other fields too, depending on customer type, features, and form setup.
Click Save. NetSuite refuses the save and names Terms as missing. In NetSuite this is a browser alert; the recording shows the same message drawn inside the page. The wording can differ, and it lists every required field that's still empty, so you may see more than Terms.
05. Choose Terms and save
Click OK and open the Financial subtab. Terms carries the required-field asterisk. Choose Net 30, or whichever term this customer should have.
Click Save. In this example the customer saves as 1204 Granite Bay Supply with Custom Form showing AR Customer Form. Your account assigns its own customer number.
On the saved customer's Financial subtab, Terms shows Net 30.
To check your own setup, confirm that the form appears as preferred in Entry Forms, that a new customer opens on it, that Save is refused while Terms is empty, and that the saved customer shows the Terms you chose. Run the same test with a role that actually creates customers, such as a sales rep role, not only Administrator. Then go back and fill in Terms on existing customers like Brookfield Hardware.
Common questions
Does a mandatory Terms field stop CSV imports without Terms?
Not reliably. The requirement lives on the entry form, and CSV imports, web services, integrations, and SuiteScript may not apply it the same way. If every customer needs Terms, test each channel and validate Terms there, or add a check that runs on the server.
Why doesn't a new customer open on my preferred form?
A preferred form set on the user's role wins over Form is Preferred on the form itself. Users can also pick another available form from Custom Form. Check the role's form settings and which forms that role can use.
How do I fix existing customers with blank Terms?
The form change doesn't backfill anything. Build a customer search filtered to an empty Terms field, then update those customers by hand or with a tested import. Editing one of them on the new form will also ask for Terms before it saves.
Can I make Terms required on every customer form at once?
Not from one form. Mandatory applies only to the form you edit, so repeat the change on every customer form people can use, or limit which forms they can use. To enforce Terms regardless of form or channel, use a workflow or script.
Does the customer's Terms carry over to invoices?
Customer Terms is the usual default for payment terms on the customer's transactions, including invoices. Depending on the transaction form and setup, someone can still change it on the invoice, so check the invoice too.
Why is the Mandatory box greyed out on some fields?
Some fields are always required by NetSuite, and the form editor won't let you make them optional. In the example, Primary Currency shows a greyed, checked Mandatory box for that reason. You can only change Mandatory where the checkbox is active.