Hi@akhtar,
You need to use the setup module to do this task. This module has the capability to gather information on remote nodes. You can use the below-given command to find the memory of remote nodes.
$ ansible server -m setup -a 'filter=ansible_*_mb'
192.168.0.180 | SUCCESS => {
    "ansible_facts": {
        "ansible_memfree_mb": 5723,
        "ansible_memory_mb": {
            "nocache": {
                "free": 6711,
                "used": 1262
            },
            "real": {
                "free": 5723,
                "total": 7973,
                "used": 2250
            },
            "swap": {
                "cached": 0,
                "free": 8103,
                "total": 8103,
                "used": 0
            }
        },
        "ansible_memtotal_mb": 7973,
        "ansible_swapfree_mb": 8103,
        "ansible_swaptotal_mb": 8103,
        "discovered_interpreter_python": "/usr/libexec/platform-python"
    },
    "changed": false
}