Sample Code:

Map<String, System.OrgLimit> orgLimitMap = OrgLimits.getMap();
System.debug('OrgLimitMap-' + orgLimitMap);

for(String olName :orgLimitMap.keySet()) {
    System.OrgLimit orgLimit = orgLimitMap.get(olName);
    System.debug('Org Limit Name: ' + olName);
    System.debug('Org Limit Used:' + orgLimit.getValue());
    System.debug('Org Limit Available:' + orgLimit.getLimit());
}