How do i write to a manga author in Japan?

Hi,
I was wondering how i write a letter to a manga author. I'm not sure what format i should write the letter in and i'm also not sure how i should write the address. I want to write to Adachitoka, authors of Noragami, as one of the duo is very sick i want them to know that the fans are wishing for her recovery and still support them despite the indefinite hiatus!
I know that the publishers of the manga are Kondansha... but im not too sure about the format of the letter and how to address it, as i said.
It would be great to get some help with this!

Thank you!

How to :
https://www.japan-guide.com/forum/quereadisplay.html?0+153784
https://www.japan-guide.com/forum/quereadisplay.html?0+132422

This is Noragami TV-animation series director's tweet.
https://twitter.com/kaiinu/status/756457310713622529
This is another editorial department of Kodansha's a guide of fan letter.
http://aoitori.kodansha.co.jp/fanletter/
But "Monthly Shonen Magazine(月刊少年マガジン)" web(serialized Noragami) has not
online "mail form", so you have to write and send a regular "air mail".
http://www.shonenmagazine.com/

format?
Normal letter style, enough.
Most foreign fans write in their native lang, so no need to translate into Japanese.
Also you can send own illustrations and some photos with.

In Kadokawa(another big book company) web said "(note!) We can not receive other than letters",
https://www.kadokawa.co.jp/support/c/
but such note is not written in Kodansha web, however, it should be considered the same.
This is another manga author's blog, so it may be recieved if it small.
http://fujihiron.jugem.jp/?cid=4