Yes, you can absolutely use Psylio as an intern or doctoral student.
If you are part of a group organization in Psylio, you can:
The note approval feature allows your supervisor to review and approve your notes directly in Psylio.
To learn more, see the following article: How does note approval work?
Currently, Psylio only supports one signature per invoice. The signature displayed on the invoice will be the one belonging to the person who created it.
However, you can still: