Do you mean that you do not get a drop-down list with suggestions if you start typing in the location bar ?

Did you check the settings for the location bar in "Options/Preferences -> Privacy & Security" ?

You can check for problems with the places.sqlite and favicons.sqlite files in the Firefox profile folder.

• use "Verify Integrity" button on the "Help -> Troubleshooting Information" (about:support) page

If errors are reported with "Verify Integrity", close and restart Firefox and retry.

See also this bug report.

• Bug 1614839 - Firefox 74 Beta 1 address bar no longer has drop down menu

(please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html)