example of field describes to get a field name

gistfile1.cls

Schema.DescribeSObjectResult d = Schema.getGlobalDescribe().get('Task').getDescribe();
 
Map<String,sObjectField> fields = d.fields.getMap();

for (String f : fields.keyset() ) {
    Schema.DescribeFieldResult dfr = fields.get(f).getDescribe();
    //system.debug(JSON.serialize(dfr));
    system.debug(dfr.Name);
}