@Thavha Tshitimbi - I am going to assume that by “file” you are referring to a Miro board. Without seeing how big your board is-- and by “big” I mean, how much stuff is in it-- and how you have it laid, out, I would suggest

1. putting your board contents into frames
2. then exporting the board as a PDF
3. and sending that PDF to your friend using your preferred method of transmission (email, WhatsApp, etc.)

Here is a post with some information about creating frames and exporting the board to PDF:

https://community.miro.com/got-a-question-ask-the-community-45/how-to-set-board-as-a4-2083 

And some Miro help articles:

• Frames
• Board Export