If you are not familiar with modules, check out Ansible - Getting Started with Modules.

Prerequisites

• Before you can use the Ansible Amazon Web Services (AWS) modules, you will need to install the AWS CLI tool on the hosts that will be using the Ansible Amazon Web Services (AWS) modules. Check out my article on Getting Started with the Ansible Amazon Web Services (AWS) modules.
• You will also need to set your Amazon Web Services (AWS) Profile Configurations. Check out my article Set Amazon Web Services (AWS) Profile Configurations.
• The aws_s3_bucket_info requires the following packages. Check out my article Resolve "boto3 required for this module".
  • botocore version 1.25.0 or higher
  • boto3 version 1.22.0 or higher
• Python 3.6 or higher must be used. The ansible --version command can be used to list the version of Python being used with Ansible. If your Ansible installation is used a version lower than Python 3.6, one solution would be to install Ansible in a Python virtual environment using Python 3.6 or higher.
• The amazon.aws collection will need to be installed. Check out my article on Install a collection using the ansible-galaxy collection install command.

Before creating an alarm, you will need:

• The Amazon Resource Number (ARN) of one of your AWS Simple Notification Service (SNS) Topics
• The ID of one or more of your EC2 instances

cloudwatch_metric_alarm can be used to create an Amazon Web Services (AWS) Cloudwatch Alarm. 

---
- name: main play
  hosts: localhost
  tasks:
  - name: pip install boto3
    pip:
      name: boto3
      state: latest

  - name: create Cloudwatch alarm
    amazon.aws.cloudwatch_metric_alarm:
      state: present
      region: us-east-1
      name: high-cpu
      metric_name: CPUUtilization
      namespace: AWS/EC2
      statistic: Average
      comparison: GreaterThanThreshold
      threshold: 50.0
      period: 300
      evaluation_periods: 2
      unit: Percent
      description: "EC2 Instance CPU exceeds 50%"
      dimensions: {"InstanceId":"i-09e2eabcdf1481234"}
      alarm_actions: ["arn:aws:sns:us-east-1:123456789012:my-topic"]
...

absent can be used to delete an alarm.

---
- name: main play
  hosts: localhost
  tasks:
  - name: pip install boto3
    pip:
      name: boto3
      state: latest

  - name: create Cloudwatch alarm
    amazon.aws.cloudwatch_metric_alarm:
      state: absent
      name: high-cpu
...