Try with this

 24/12/2022

My Dear Mutsumi, 

I'm so happy receiving your mail!

I don't know what is my ID for "line".

I have found a QR code though...

Try with it if you can.

However my telephone number is +393478825261 

And there is also this link. I really don't know what it is:

https://line.me/ti/p/saQeXBjOgH

Bye!