Wordpres Post Details page add-on button and password protected

hi wordpress post details page need to add-on button for download video or file and it will be password protected. when user click on download button then user name and password prompt will show. user name and password come from wordpress database table which I will upload time to time my excel file user list. excel file there 4 column only like mobile, user name, password, status status active only can download. database may be 100 user but when I feel 20 user which inactive then I will upload excel file from admin panel which u need to give option. only 20 data will update not others. if not clear then I will talk over chat then explain.