jot down
To write something down, often in haste. A noun or pronoun can be used between "jot" and "down." Let me just grab a pen so I can jot that number down. Here, I jotted down some ideas for you.
jot something down
to make a note of something. This is important. Please jot this down. Jot down this note, please.
jot down
v. To write down something briefly or hastily: The secretary jotted the message down. I jotted down the homework assignment.