As far as I know the best software wallet for BTC holding is coinbase wallet.

"IN BRIEF
Founded in June of 2012, Coinbase is a digital currency wallet and platform where merchants and consumers can transact with new digital currencies like bitcoin, ethereum, and litecoin. We're based in San Francisco, California.

Bitcoin is the world's most widely used alternative currency with a total market cap of over $100 billion. The bitcoin network is made up of thousands of computers run by individuals all over the world."
To get your wallet or know more visit here: https://www.coinbase.com