Firefox can remember what you've entered in forms on web pages, also known as text fields. After you've entered something into a form on a web page (such as a search box), the next time you visit that page, your previous entry will be available to re-use. This article describes how to use the auto form fill feature and how to clear or prevent it from storing form entries.

Using Auto Form Fill

To use your previous entry in a form:

1. Type the first few letters of the entry into the form field. Firefox will display a drop-down menu with what you've typed into the form before.
   • You may see a list of all the entries stored for a particular form field by pressing the ↓ key when the field is empty.
2. Press the ↓ key to select the entry you want to re-use. Press EnterReturn when the appropriate entry is highlighted. The text of the entry will appear in the form field. You may also use the mouse to click on the entry.

Deleting individual form entries

If you want to remove one of your previous form entries from Firefox's history:

1. Click on the form field and press the ↓ key to display all the saved entries. You may type the first few letters of the entry to limit the number of entries displayed.
2. Use the ↓ key or the mouse pointer to highlight the entry you wish to delete.
3. Press Shift+Delete. The entry will be removed.

Repeat the process for each entry that you'd like to delete.

Clearing form history

If you want Firefox to forget all of your previous form entries:

1. Click the menu button to open the menu panel.
2. Click History, and then click Clear Recent History….
3. In the Time range to clear: drop-down, choose Everything.
4. Make sure that Form & search history has a check mark next to it.
5. Click OKClear Now to clear your form history and close the dialog box.

Turn off Auto form fill and prevent Firefox from storing more form entries

If you don't want Firefox to remember what you've entered into form fields, you can turn off the auto form fill feature:

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the Privacy & Security panel.
3. In the drop-down menu next to Firefox will, choose Use custom settings for history.
4. Remove the check mark next to Remember search and form history.
5. Close the Settings page. Any changes you've made will automatically be saved.

Disabling form history also prevents Firefox from storing search history for the Search bar in the Navigation Toolbar.

Troubleshooting

If you find that Firefox does not save your form entries and you cannot re-use them, please read the article Firefox doesn't save web form entries.

Based on information from Deleting autocomplete entries (mozillaZine KB)