Use web3.js

import Web3 from "web3";
import { ethereum, InstallError } from "@cosmostation/extension-client";
try {
  const provider = await ethereum();
  const web3 = new Web3(provider);
  // requestAccounts
  const accounts = web3.eth.requestAccounts();
  // If you want more info, please check out web3.js docs (https://web3js.readthedocs.io)
} catch (e) {
  if (e instanceof InstallError) {
    console.log("not installed");
  }
  // exception
}

const provider = await ethereum();
 
const web3 = new Web3(provider);
 
const msgParams = JSON.stringify({
  domain: {
    // Defining the chain aka Rinkeby testnet or Ethereum Main Net
    chainId: 1,
    // Give a user friendly name to the specific contract you are signing for.
    name: "Ether Mail",
    // If name isn't enough add verifying contract to make sure you are establishing contracts with the proper entity
    verifyingContract: "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC",
    // Just let's you know the latest version. Definitely make sure the field name is correct.
    version: "1",
  },
 
  // Defining the message signing data content.
  message: {
    /*
         - Anything you want. Just a JSON Blob that encodes the data you want to send
         - No required fields
         - This is DApp Specific
         - Be as explicit as possible when building out the message schema.
        */
    contents: "Hello, Bob!",
    attachedMoneyInEth: 4.2,
    from: {
      name: "Cow",
      wallets: [
        "0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826",
        "0xDeaDbeefdEAdbeefdEadbEEFdeadbeEFdEaDbeeF",
      ],
    },
    to: [
      {
        name: "Bob",
        wallets: [
          "0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB",
          "0xB0BdaBea57B0BDABeA57b0bdABEA57b0BDabEa57",
          "0xB0B0b0b0b0b0B000000000000000000000000000",
        ],
      },
    ],
  },
  // Refers to the keys of the *types* object below.
  primaryType: "Mail",
  types: {
    // TODO: Clarify if EIP712Domain refers to the domain the contract is hosted on
    EIP712Domain: [
      { name: "name", type: "string" },
      { name: "version", type: "string" },
      { name: "chainId", type: "uint256" },
      { name: "verifyingContract", type: "address" },
    ],
    // Not an EIP712Domain definition
    Group: [
      { name: "name", type: "string" },
      { name: "members", type: "Person[]" },
    ],
    // Refer to PrimaryType
    Mail: [
      { name: "from", type: "Person" },
      { name: "to", type: "Person[]" },
      { name: "contents", type: "string" },
    ],
    // Not an EIP712Domain definition
    Person: [
      { name: "name", type: "string" },
      { name: "wallets", type: "address[]" },
    ],
  },
});
 
const from = ""; // signer address
const params = [from, msgParams];
const method = "eth_signTypedData_v4";
const result = web3.currentProvider.request({
  method,
  params,
});