What it does, precisely
It records each copy. The app watches the system clipboard and saves a copy of every item you put there: text, links, images, files, rich text from a document. Each entry keeps where it came from, so you can tell the two similar-looking snippets apart later.
It gives you the list back on a shortcut. You press a key combination, a small window appears with your recent items, you pick one and it pastes into whatever you were typing in. Good ones let you type a few letters to filter, so finding an address you copied an hour ago takes about two seconds.
Some of them do more than remembering. Pasting without formatting, saving snippets you reuse, reading text out of a copied screenshot, cleaning up line breaks from a PDF. Those are extras. The list and the shortcut are the product.
It stores the history locally by default. In most Mac clipboard managers the history is a database file on your own disk, with no account and no server involved. Sync between devices exists in some of them and is normally something you switch on.
What macOS 26 Tahoe added
The clip shows a searchable history list with the copied item's source app and content type visible on each row. Filtering by type matters more than it sounds, because a day of copying produces mostly text and the one image you want is buried in it.
Images are the part built-in history does not cover. A copied screenshot has to be stored outside the database and looked up by content hash, otherwise the history file grows enormous and the same image gets saved four times.
macOS 26 Tahoe added a clipboard history to Spotlight. Press ⌘Space to open Spotlight, then ⌘4, and you get your recent copied items. It keeps them for 8 hours by default, and the retention choices are 30 minutes, 8 hours or 7 days. It survives a reboot. The Clipboard switch lives in System Settings under Spotlight, so that is where to look for it.
The limits are worth knowing before you decide you are done. It handles plain text only, so copied images and files are not in there. There is no text recognition inside a copied screenshot. And it is macOS 26 only.
On macOS 15 Sequoia and anything older there is no built-in clipboard history at all. Nothing hidden in a menu, nothing to enable. If you are on Sequoia, a third-party app is the only route. There is no macOS 25, in case a search result told you otherwise.
Who does not need one
If you copy a handful of times a day and you always paste immediately, macOS is fine as it is. The single slot only hurts when there is a gap between copying and pasting, or when you need two things at once.
If you are on macOS 26 and your copying is all plain text, the Spotlight history probably covers you. Try it for a week before you install anything. I would rather you use the free thing that came with your Mac than pay for a feature you already own.
The honest case for a separate app is images, longer retention, search that goes back further, and doing something to the text on the way out. If none of those describe your day, skip it.
The privacy part, said plainly
A clipboard manager sees everything you copy, and that includes passwords. Most managers store history unencrypted on disk, and most password managers mark their copies so a well-behaved clipboard app ignores them. Two things follow from that. Check whether your manager keeps history locally or syncs it somewhere, and check whether it has an exclusion for password managers and whether that exclusion is switched on.
Copying a password out of a manager into a clipboard manager's permanent history is the mistake worth avoiding. Everything else on the list is low stakes.
What I would install
Maccy is the free answer, and it is a good one. Open source under the MIT licence, about 1.6 MB, history capped at 999 items with a default of 200. Search, a shortcut, and nothing else asking for attention. Get it from maccy.app, its GitHub releases page, or brew install --cask maccy in Terminal. Never download it from a domain that looks similar to that one, because impersonating sites exist and they serve malware.
I used Maccy for years and kept wishing it did a few more things, so I forked it and built Klipto: a hold-to-paste popup on ⌥⌘V, images that survive a restart, text recognised inside a copied screenshot on ⇧Enter, and a queue that pastes several collected items in order on ⌃⌘V. It is $19.99 once with a free tier and a 14-day trial. If your list of complaints about Maccy is empty, stay on Maccy.