Receiving COE while in Japan

Hello I am Luka from Japan, currently working in Japan from last 2 years.
I applied for spouse visa in December for my wife. I have been working in Japan with valid working visa which is until 2020.
Today I got unattended item notice ( from JP post ) . I wasnt at home.
Its merely been a month , and I got some notice from immigration .
I want to know will it may contain rejection letter or COE ?
As there was no one at home to receive the mail, it is def IMPORTANT matters. But I would like to know from those who obtained their COE for Spouse visa, how did they receive it?
Did they receive from same postal mail , or will you get that small card , where you have to take and go immigration again ?
Thank you

COEs are sent by postal mail. However, a COE is used by those applying for a visa outside of Japan. In your case, you should - instead - apply for a "change of residence status" at an immigration bureau inside of Japan. At least this is my understanding.

The question is a bit confusing but I understood that, Luka, you are working in Japan on a work visa, and you applied for �gdependent�h visa for your wife? And as the applicant, Luka should receive the CoE for the wife (who is outside Japan now?)
For �gchange of resident status�h or renewal, you receive a postcard. For others, it would come in an envelope, and I believe it needs to be handed in person.

since you were absent, you got �s�ݒʒm.
the easiest ways to collect the letter:
1. ask the help by your Japanese friend to call post office. (reply phone is a bit complicated. need complete understanding of the language.)
or
2. go to �W�z�X�֋ǁ@with that slip and your ID which shows your address.

if you don't do that, the letter will be returned to the sender after (about) 1 week.

Simple - take the notification to the post office indicated and get the item. Then you will find out what the mail is. Picking up registered mail is a simple/common thing.