Emacs has several different facilities to navigate around arbitrary points in a buffer.
The first and most obvious is the mark. Emacs keeps both a buffer local mark ring and a global mark ring. You can set the mark at the current point with C-SPC and it will be recorded in both rings. You can then “pop” back through the points in the local mark ring with C-u C-SPC, or through the points in the global mark ring with C-x C-SPC. The mark rings do not persist across Emacs sessions. See (emacs)Mark.
The next is registers. Registers can save points, but also text, numbers, and a bunch of other things. For now we’ll just focus on points. You can record a point in a register with C-x r SPC X where X is any keyboard character. Registers do not persist across Emacs sessions. See (emacs)Registers.
You can also always insert a note with arbitrary text, e.g.
[[marker: next]], and this will be navigable via Imenu.
See Notes.