Can we get an in-game sticky note/reminder function?

[ItMe]

Write is as a macro, name it Notes.

/echo This is a note I am writing to myself.

You can put it on a hotbar and bam, instant reminder as when you click it you'll get "This is a note I am writing to myself" right there in chat!
If you set it to macro #0 you can even include the command to open your macro list and edit it any time as it'll be the first one open.

/macros
/echo This is a note I am writing to myself
/echo It's pretty neat!

Is there a way to write that where I don't share my note with the party when I click on it?

[Iscah]

/echo just sends it to your chat, not the party chat. You'd need to use /p for that to happen.

You don't "need to use /p" to accidentally send things to party chat - you just need to forget to put something else.

Is there a way to write that where I don't share my note with the party when I click on it?

The easiest way is to set up your "sticky note" macro in advance with /e (for "echo") at the start of every line to ensure that particular line will always display as echo text regardless of your current chat channel.

I have a blank one saved as a template and I'll copy it to another slot if I want to start taking notes.

[Mhaeric]

You don't "need to use /p" to accidentally send things to party chat - you just need to forget to put something else.

And for my tangentially related nitpick to your tangentially related nitpick, that is only the case if your default chat is set to party.

[Canadane]

Is there a way to write that where I don't share my note with the party when I click on it?

As others have said, /echo only gives the message to yourself.