Hi, you can try this method:

Clearing all items in the address bar history 1. Click on the menu button -> Click History.

2. Click Clear Recent History... to open the dialog window.

3. In the Clear Recent History window, set Time range to clear: to Everything.

4. To remove browsing history, make sure Browsing & Download History has a check mark next to it. To remove Search history -> check the box next to Form & Search History.

5. To clear all items in the address bar history, click OK.

You can refer this two website: https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox

https://support.mozilla.org/en-US/kb/remove-websites-address-bar-suggestions

Thanks cy6566.

I did what you told me. .Unfortunately nothing has changed.

When I write in the mid-screen search window, the writing displays at the top of the address bar.

Hi, can you try on this method see whether can solve your problem:

1. Go to menu -> Click Settings -> Click Search

2. You will see Search Suggestions -> Uncheck the Provide search suggestions