How can I export only my notes from the Notes app and import to another Mac?

Is there an option to save notes to iCloud?

Yes, in system preferences-> iCloud.
It seems I cannot import a pdf to notes.

You can. The regular method of File-> import->import file, won't work. You can drag and drop multiple files into a note.
Scripting.

That would be a task for AppleScript.
How to import the notes to new Mac?

If the same Apple ID is used on both Macs, turn on the iCloud for notes (see 1^). They'll sync. If different IDs are used, there is no easy method. You can add collaborators (or people) and send them the invite. Then they can import all the notes to their Mac.

There is an app on the app store named Note2Txt that will convert each note to a text file and save it to a directory/folder of your choice. The app is $0.99 and is extremely fast and efficient. I back up my notes using this app. Each text file is given the name of the note with extension .txt

Homeomorphism between open unit ball and $\mathbb R^n$

Is there a classification of isolated essential singularities?

Isomorphisms between Normed Spaces

Finding the coordinate vector relative to a given basis

Cholesky of matrix plus identity

Proving that a polynomial of the form $(x-a_1)\cdots(x-a_n) + 1$ is irreducible over $\mathbb{Q}$

Is it possible to find indefinite integral of $\int \frac{1} {{\sin(x)+\sec^2(x)}}\mathrm{d}x$?

Why is second smallest eigenvalue and the corresponding eigenvector used to partition a graph?

Decomposition of an algebraic number into a sum or product of algebraic numbers with smaller degree

Prove conjecture $a_{n+1}>a_{n}$ if $a_{n+1}=a+\frac{n}{a_{n}}$

Another beauty hidden in a simple triangle (2)

"Continuized" Taylor Series? $\sin(x)=\sum \frac{(-1)^nx^{2n+1}}{(2n+1)!}=\int_{-1}^\infty \frac{\cos(\pi n) x^{2n+1}}{G(2n+1)}dn$?