Dear Jade,
Yes you can export an instrument from any of your REDCap project as a .zip file and then import it in another project (be it yours or not).
For that purpose, go to the 
then click on "Download instrument ZIP" for the instrument you'd like to export:
Then, go to the project where you want to import the instrument and, again under , click on:
To share the instruments with someone else, I'd encourage you to use SWITCHDrive or SWITCHFilesender which are freely available to UniFR members.
Best wishes,
C.