I see that below link lists lots of directives that can be used. https://docs.ansible.com/ansible/playbooks_directives.html
Howerver, i am not able to find the example/explanation of these directives.
Is there any documentation, that explains about these directives?
There is no directly link to each but they should all be documented as part of the rest of the docs. i.e become_, sudo_, su_* ones are all in the ‘privilege escalation’ page.