Often your end users want to enter all pertinent information together, even if the data lives in separate tables. For example, when you create a new meeting, you want to add related agenda items at the same time and save all those records in a single click. You can easily grant the ability to add data to multiple tables from within a single form.

Enter it all on a single screen. This meeting
record features an embedded report of related agenda items.
Even though agenda details live in a separate table, you can add them at
the same time you create the meeting.
To add a new agenda item, start typing in any blank line at the bottom
of the embedded report.
To grant users the ability to add and edit related records, embed report(s) of related detail records on the master form and make it editable. This means the report appears in grid edit mode when the master form is in add or edit mode.
Before you enable spreadsheet-style editing and adding of related detail records, be sure that's what you want. This feature can really help your users work faster and more efficiently, but there are a few reasons that an application manager may not want to implement grid edit on a form. Don't enable this feature if:
Form Rules are an important part of entering detail records. Form rules don't work in grid edit mode. If you have form rules set on your detail form that you need to enforce, don't make your embedded report editable.
You want the embedded report to total or average detail records. Grid edit views don't show totals or subtotals.
Users need to see detail formula fields update dynamically as they work. On a form, formula and calculated fields update their values immediately based on entries you make in their sub-fields (even before you save). In grid edit, calculated fields don't update until you save all changes.
Detail records include file attachments. If your detail table stores documents, enabling this feature won't do you much good, since you can't upload documents in grid edit mode.
If it doesn't already exist, embed a report of detail records on the master form.
Make that report editable.
Within the form builder, select the report link field for the embedded report and turn on the Editable checkbox in the right-hand pane.

In this illustration, Tasks is the report link
field that shows a report of related task records.
When you select the Tasks field on the left, QuickBase
shows the field type (Report Link) at the top of the right-hand pane
along with info and controls including the Editable
checkbox.
Remove old URL - formula "add detail record" fields.
If your form already featured an embedded details report, you probably also included a URL formula field that let users add a new detail record. (These fields look like buttons or hyperlinks.) Since users will be able to edit and add detail records directly through the editable embedded report, you should remove the old URL formula field.

When you make an embedded report, like Agenda Items,
editable, you should remove old URL formula fields that used to accompany
the report.
In this case, you'd remove the e Add Agenda Item field
from this form. Doing so will cut down on user confusion.
Save changes.
Click Save & Done to save and return to the form.
The master form now lets you edit and add detail records spreadsheet-style.
NOTE: Editable reports don't display in Grid Edit mode when you merely display the master record form. Like any other data-entry field on the form, embedded Grid Edit reports are only editable when you're editing or adding a master record.