Hi, @Makiko ! The short answer is, "Just like they were stocks or mutual funds." Income from the sale, exchange, or use of crypto is taxed as either a short- or long-term capital gain, depending upon whether it was held for more than a year, or one year or less.
I'm assuming that's what you mean by "investment income", but do be aware that if you received any other crypto-related income (e.g. airdrops, incentives, hard forks, etc.), those are taxed as ordinary income (which is generally a higher rate).
Hope this helps!
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"