good start

roles/ssh-key-copy/tasks/copy.yml

@@ -0,0 +1,7 @@
+- name: add ssh keys
+  ansible.posix.authorized_key:
+    user: "{{ ansible_user }}"
+    state: present
+    # copy file present on the controller to the remote host
+    # https://docs.ansible.com/ansible/latest/collections/ansible/builtin/copy_module.html
+    key: "{{ lookup('file', '~/.ssh/default.pub') }}"

roles/ssh-key-copy/tasks/main.yml

@@ -0,0 +1,2 @@
+- name: copy
+  include_tasks: copy.yml