Some of services still using basic auth. For generate credentials for webserver (apache/nginx) need to use special utility – htpasswd
At first, install htpasswd. For Debian based distributive command for apt:
sudo apt-get update && sudo apt-get install apache2-utils
After installation for create new file with credentials use:
htpasswd -c credentials.passwd user_name
For existing file just run:
htpasswd credentials.passwd user_name new_user_name
After this created file credentials.passwd can be used for Nginx or another services.