Written notification about tried delivery of a letter or package which can only be received in person. If you are not home, you can go to nearest post office and receive it there. Sorry, I thought it's english word.
In English "advise", alas, not used in the common language in regards to mail, like it is used in Polish (and Czech?).
Collins ...in British English (əˈvaɪzəʊ) - NOUN
"a boat carrying messages; a dispatch-boat"