IF the email is for a google account, you can log in with that account, open the form and go to Responses. Click the 3 vertical dot icon right above the Accepting responses option and choose Get email notifications for new responses.
In one comment you state you have tried using form add-ons. I know Email Notifications for Forms has been used by many and is well received. I mention it in case you have not tried this particular add-on. I do not use this, but use custom script.
There are custom script options available as tutorials or sample code which could send to any email and the address can be in any location in the spreadsheet or hard coded in the script (not recommended). You could use the code in the Tutorial: Simple Mail Merge to accomplish your goal. I used this as a base and have had a lot of success. Using that script, you can send the email to an address in the column after the last form response column. The only difference from the steps in this tutorial and what you wish is that you will not have the email as part of the form. Instead, if you have 5 questions, form data will be in columns A through F as there will be an extra column for the timestamp In cell G1, place this formula:
=ARRAYFUNCTION(IF(ISBLANK(A1:A),,IF(ROW(A1:A)=1, "Email Address", "MYEMAIL@MYCOMAIN.com")))
replacing MYEMAIL@MYCOMAIN.com with the one you wish to receive the emails.