To pass some metadata to the verification use the metadata parameter providing key value pairs like in the example below:

MetaMap.shared.showMetaMapFlow(clientId: "YOUR_CLIENT_ID",
				flowId: "YOUR_FLOW_ID",
				metadata: ["key1": "`value1","key2": "`value2"])
MetaMap.shared.showMetaMapFlow(clientId: "YOUR_CLIENT_ID",
				flowId: "YOUR_FLOW_ID",
				metadata: ["key1": "`value1","key2": "`value2"])
[MetaMap.shared showMetaMapFlowWithClientId:@"YOUR_CLIENT_ID" 
			flowId:@"YOUR_FLOW_ID"  
			metadata:@{@"key1":@"value1"}];