External URLs won't be available. However, the ansible-doc command is your friend always, if/ once Ansible is installed on the control node. For that, you will want to consider the steps you'll need to take to have Ansible installed on your control node, if Ansible isn't installed and ready to go in an exam environment:
yum list installed platform-python (or) yum install platform-python (if it's not installed)
subscription-manage repos --enable ansible-2-for-rhel-8-x86_64-rpms
yum install ansible
Reminder: you can get a list of available docs with:
ansible-doc --list (and type: /searchstring i.e. /vars and find docs related to variables), searching its less format output.
Just like Robert mentioned your best friend for modules will be Ansible-doc -l command to list modules and search for the one of interest and as for all things Ansible in the exam there is documentation that can be referenced just not external. Please review the exam objectives in careful detail as everything you need to know is there.