You can purchase BTC at Coinbase, http://coinbase.com; I haven't used other on-ramps myself, although I've heard there are better ones now. You'll need to link a bank account, and perhaps other AML/KYC/KMA forms and photo IDs et al.
If you just want a wallet for your computer, this should help: https://www.bitcoin.com/choose-your-wallet/bitcoin-com-wallet?utm_source=get-started&utm_medium=card&utm_content=wallet
Ok. Thank you. With time i will learn more from you about it.