how to give non root user full permission for ftp

hi, somehow i delete a folder & all its files from filezilla. now i cant upload any files to that folder using non root user. it always says

Error: /wp-includes/js/zxcvbn.min.js: open for write: permission denied Error: File transfer failed

but when i login using root user, all files of that folder is there. how can i give root permission to that user so that it can write/change anything through filezilla just like root user.

i just checked the folder permission by “ls -l” and it was like this

-rw-r–r-- 1 www-data www-data 324 Jan 30 16:38 zxcvbn-async.min.js -rw-r–r-- 1 www-data www-data 698775 Jan 30 16:38 zxcvbn.min.js

any idea how can i make my non-root user to upload files there?