So, wordpress sites do not need chmod 777, as some customers do use. Traditionally, you will want to create permissions in accordance with this document:

https://codex.wordpress.org/Hardening_WordPress#File_Permissions

The most important pieces are chmod for folders and chmod for files using find to do this en-masse

D for directories

find /path/to/your/wordpress/install/ -type d -exec chmod 755 {} \;

F for files

find /path/to/your/wordpress/install/ -type f -exec chmod 644 {} \;