Where can I find" your personal residence information" page and add the information of "county" field? I have never entered any information about "county".

Your mailing address is entered in "My Info", but it does not have a entry for your County.  That would be in the State section.  The exact location depends upon the state.  For example, Maryland asks on the very first page, Georgia Does not ask.  Without knowing what state your in, I can't tell you exactly where to enter your county of residency.

Open turbotax and select "State Taxes" in the top menu.

The next page will have, "Let's work on your state refund." Select "Continue."

The next page is labeled, "State Return." Your state should appear and to the right is an "Edit" button.  Select "Edit."

This will bring up a page, "Your 2022 Maryland taxes are ready for us to check."

The "General Info" appears at the top and to the right is an "Edit" button.  Select "Edit."

The next page will ask you to confirm your residency status.  Select "Continue" bottom right.

The next page prompts you to enter "County" and your "Physical" address.  You already entered your mailing address in the "Personal Info" section before beginning your Federal taxes. Fill out and select "Continue."

The next page asks "Tell Us Your Local Taxing Area." A drop down menu allows you to select your City or Town. Select "Continue" when finished.