You need to enable import CSV in the Password Manager (about:logins) via the about:config page as this menu item is currently hidden for performance reasons.

• about:config => signon.management.page.fileImport.enabled = true
• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

You need to close and restart Firefox to make the Import menu item appear in the gear menu on the about:logins page.

Thank you but too technical do not understand. We cannot find "password manager"

The Password Manager is the page that opens if you click Passwords in the "3-bar" Firefox menu button drop-down list. You can also type/paste about:logins in the address bar.

• https://support.mozilla.org/en-US/kb/password-manager-remember-delete-edit-logins