I look for mumbai or its chain ID 8001 at chainlist.wtf according to suggestions on MetaMask site but is not there. I guess only no testnet Networks are there, so what would be the equivalent for developing or what links Metamasks would recommend?
Try the site 
connect wallet and add network…
https://chainlist.org/?search=Mumbai&testnets=true
Thanks Luigi, It worked, it added rpc-mumbai . maticvigil . com / link
Hello, Luigi has replied to you, you can also check the balance of the test network from your wallet address at the test network
Please use English, we don’t have support for other languages atm