My question is how to send file to my teacher if the Recipient name is invalid?
My question is how to send file to my teacher if the Recipient name is invalid?
alfomso Dizom 
Are you using the Inbox built into Canvas to send your teacher the file?
If so then your teacher's name ought to appear in the contacts.
This guide will help.
How do I send a message to a user in a course in the Inbox as a student?
When you click on the Contacts then Teachers and Students will appear as options. If you click on Teachers then your teacher's name will appear. Click on that then your message will begin.
Sing out if you need a hand.
alfomso Dizom
Welcome to the Canvas community.
Are you using the Inbox built into Canvas to send your teacher the file?
If so then your teacher's name ought to appear in the contacts.
This guide will help.
How do I send a message to a user in a course in the Inbox as a student?
When you click on the Contacts then Teachers and Students will appear as options. If you click on Teachers then your teacher's name will appear. Click on that then your message will begin.
Sing out if you need a hand.