Saved Locations in EVE Online are often called Bookmarks or BMs.

To save a BM of a location, right-click it in space or on the overview → Save Location. To save your ship's current location in space, hit Control + B then Enter.
To access saved BMs: right-click them in space or the Solar System Map (F9), right-click empty space & hover Locations, or use the Locations or Local Locations windows.
L is the default Locations shortcut. Local Locations, which shows only BMs in the current system, is unbound (Escape → Shortcuts → Window → Local Locations).

Bookmark Barn and Jet-Perches sell BM packs for all regions in EVE. I'm unaffiliated.
Name your BMs systematically so they're unambiguous and easy to understand at a glance.
Click to show/hide some semantic fluff about my terminology & rationale.
Safe i.e. safespot best describes a BM intended to hide you or keep you as far from commonly-visited grids as possible.
BMs which are deliberately on or near a grid—so you can see and/or dscan what's happening there—are better described as bounces, perches, pings, tacs, etc.
Likewise, instadocks and insta-undocks are sufficiently different from either of the above that their terms shouldn't be muddled.
There's some ambiguity/overlap here, but my point is that BMs have different use cases, and you should name them systematically to avoid pointless future fuckups.
e.g. you wanna surreptitiously dscan an outgate in a non-covert hull. You have both a gate perch and an off-grid perch in the cluster. You wanna use the latter.
However, if your BMs in the gate cluster are just called "gate close" and "gate near", how do you know which is which?
Develop a non-ambiguous naming scheme before you make the BMs and stick to it. Then you won't have to worry about such nonsense in the heat of the moment.

Instadock

Vital for stations, especially trade hubs, frequent HS haunts and all LS, NS, Pochven and Thera stations. Also nice (but not always vital) for structures.
If you don't use instadocks, about half the time you attempt to dock, your ship can be instantly destroyed before it can do so.
Click to show/hide an explanation of why.

Insta-undock

Also vital for stations, since ships can be destroyed at any station in EVE while aligning for warp after undocking and warping off.

Perches

AKA bounces, pings, tacs, tacticals. They're for visually surveying grids, dscanning grids without appearing on them, and/or juking interdiction/smartbombers/lancers.
Objects near a destination (e.g. planets, moons, structures) can be useful ad hoc perches, but not always! Competently-made perch BMs will almost always be superior.

Safespots

AKA safes, tranquil bivouacs, cozy wilderness campfires... None of these are 100% safe! You can be probed anywhere if uncloaked, except in the Abyss.

Specialized BMs

A miscellany of BM types. A smorgasbord, a grab-bag, a gallimaufry, even.

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