IRAs can be held at many kinds of institutions, even those that you only see online.
It is completely your choice! IRAs can be opened at almost any large bank or brokerage firm, giving you plenty of options. Many online services make it possible to open an IRA from your phone or computer.
Be sure to compare them because there are some distinctions, such as fee structures and the investments available within the account. Some institutions will only offer their proprietary funds, while others will let you access almost any investment on the market that is allowable inside of an IRA.
You can also own multiple accounts, and contribute to different ones as long as you remain under the total contribution limits allowable. The IRA characterization can be placed on income annuity products, many kinds of securities, as well as some hard assets such as refined gold bullion held at an institution as well as private equity and real estate investments if the account holder does not violate self-dealing regulations.
Collectibles such as art, gems, metals, stamps, etc., are not allowable inside of an IRA.