Admin sidebar -> Stores-> Settings ->Configuration -> General-> Design, there is no HTML Head section to expand and upload the new favicon.ico! I tried to copy the favico.ico to
Magento_Theme -> web but did not help(cache was cleaned)
You can upload by following admin configuration path.
Go to Admin -> Content / Configuration -> Edit Default theme -> Go to Other Settings / HTML Head Click on 'Upload' button for Favicon Select .ico file
Hope it helps.
You can upload it from admin.
Admin >> Content >> Design >> Configuration >> Select your current theme from list >> HTML Head.
You can see here Fevicon Icon field, Upload you fevicon icon here.
Run command for clean cache :
php bin/magento cache:clean