German phrase
Ich möchte ~ teilnehmen.
Meaning
I would like to participate in ___
When to use it
It says you want to join. A polite way to express interest in an activity.
Example dialogue
Ich möchte am Austauschprogramm teilnehmen.
I would like to participate in the exchange program.
Hast du dich schon dafür beworben?
Have you already applied for it?