You create a field dependency from the controlling picklist in Object Manager, then map valid dependent values in the dependency matrix. Both fields must already exist on the same object before you start.
- Open the controlling field
In Setup, go to Object Manager, pick the object, open Fields and Relationships, and click the picklist or checkbox you want as the controlling field. Both the controlling and dependent fields must exist first.
- Add a new dependency
On the field detail page, find the Field Dependencies related list and click New. Choose the controlling field and the dependent field for this relationship, then continue to the matrix.
- Map values in the matrix
Columns are controlling values and rows are dependent values. Double-click cells, or click and drag a block, then use Include Values to mark which dependent options are valid under each controlling value.
- Preview and save
Click Preview to test the filtering, and pick a record type if you use them to confirm the combined result. When the grid looks right, click Save to store the dependency as field metadata.
- Confirm the layout
Make sure both the controlling and dependent fields sit on the same page layout. If the controlling field is missing from the layout, the dependent picklist has nothing to react to and will not filter.
A standard or custom picklist (at least one and fewer than 300 values) or a checkbox on the same record. It drives which dependent values appear.
A picklist or multi-select picklist on the same object. Its available values are filtered by the controlling selection. It can answer to only one controlling field.
The grid where you check which dependent values are valid under each controlling value, with Include Values, Exclude Values, and Preview controls.
An optional preview setting. When record types are used, a dependent value shows only when both the record type and the controlling value allow it.
- The controlling field must be on the same page layout as the dependent field, or the dependent picklist will not filter.
- Adding a dependency does not clean existing records; older rows can keep combinations the new rule would block until you fix them.
- Field dependencies are not enforced for API, Apex, or data-loader writes. Add a validation rule to catch illegal combinations from automation.
- A default value on a dependent picklist can appear even when the controlling value should hide it, so avoid dependent defaults.