-install metamask extension on your browser.
-resister to https://infura.io/dashboard/ethereum and you can select the testnet(ropsten, kovan, rinkeby...) and check the project_id
-faucet free eth to your wallet to test transaction(aucet.rinkeby.io for rinkeby, https://faucet.ropsten.be/ for ropsten, https://enjin.io/software/kovan-faucet for kovan)
from web3 ...
Your Geth version is outdated-you are likely on a "wrong", forked chain.
There was a consensus issue between nodes on Ropsten which was fixed in v1.10.6.
Even then, you may be on a "double" forked chain because of an exploit on nodes >v1.10.7. Update your node and you should be good.