ansible all --key-file ~/.ssh/ansible -i inventory -m ping -u ec2-user

Put parameters like key-file, user and inventory details in ansible.cfg, then run below commands directly by providing module names

ansible all -m ping
ansible all -m gather_facts
ansible all -m gather_facts --limit 10.145.231.4

Anisble playbook command:

ansible-playbook install-httpd.yml

add-users playbook adds users with sudo permission and also copies its ssh key

ansible-playbook add-users.yml

https://wiki.learnlinux.tv/index.php/Getting_Started_with_Ansible_13_-_Managing_Users