I don't know what knowledge base you have, and you've had a number of investing and IRA questions in the past, so I'm just going to go over a bunch of terms. Feel free to ignore it if you already know it. :)
Stocks: A tiny fraction of ownership in a company that entitles you to a tiny fraction of its profits in the form of a dividend.
Bonds: A loan to a company that pays you interest.
Mutual funds: Instead of investing in only one company, and risking losing your whole investment if that company closes, you pool your money with 1000's of other people, and buy 1000's of different stocks in order to reduce your risk. Can be either stocks or bonds, or a combination of the two.
Index Funds: A specific kind of mutual fund, that instead of having someone do research in order to pick stocks they think are going to increase in value, they just buy every stock or bond in a specific category. Like small cap, or large cap.
IRA: A type of account that gets special tax treatment. You get to claim a deduction and remove your contribution from your income so that you don't pay taxes on it. Then the money grows tax-free. You eventually pay taxes when you pull the money out in retirement. Also known as a traditional IRA.
Roth IRA: A type of IRA that handles taxes differently. You don't take a deduction, meaning you pay taxes on the money you put in this account. This money then grows tax free, and is also tax free when you pull the money out in retirement.
Taxable account: An account with no special tax treatment. Meaning you pay taxes on the money you put in the account, and pay yearly taxes on dividends. You also pay capital gains tax when you pull money out.
Accounts vs Investments: You open an account and it determines the tax treatment. Within the account, you buy investments, like mutual funds.
VTSAX: Vanguard's index fund that tracks the total stock market. In other words, VTSAX owns a piece of every company in the stock market.
Yearly limits for IRAs: In 2019, you can contribute up to $6000 in either an IRA or a Roth IRA.
Income limits for IRAs: You will need to check whether these affect you. If you make too much, you cannot contribute directly to a Roth IRA. And if you make too much, you cannot take the deduction for a traditional IRA.
I recommend you go read
JL Collins' Stock Series. Read one post every day for the next month. It's the best education for investing I know of.
Hope that helps.
