You obviously want to sell your crypto if I understood correctly, and to do that one of the most common options is to create an account at one of the famous crypto exchanges. After you send the crypto to the exchange, and sell it for fiat - you have the opportunity to make a transaction of these funds to your bank account.

Since I see you mention HMRC, it means that you are from the UK, so there is a possibility that you need to pay capital gains tax (if it exists), which will be better explained to you by someone from there.

For someone who has crypto, it's a little weird that you're not even familiar with the basics - if it's no secret how you came into possession of those cryptocurrencies?