RHEL has ansible-core, podman, and ansible-navigator in the OS repositories.

Ubuntu needs a PPA:

sudo add-apt-repository --yes --update ppa:ansible/ansible
sudo apt install ansible -y

It can also be installed with Python

sudo apt install python3-pip -y
pip3 install ansible

The default inventory path is /etc/ansible/hosts

The config is read from: ANSIBLE_CONFIG, ./ansible.cfg, ~/ansible.cfg, /etc/ansible/ansible.cfg

inventory = ./ansible_hosts  # relative to path of ansible.cfg