Oops, it doesn't look like 'writing acknowledgement of invoice for writing day' is a national day..

Other days

Bow Tie Day

Promposal Day

Believe Day

Lisp Day

Carpenters Day

Comfy Day

Ask Out Your Crush Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Tell Ur Crush You Like Them Day

Slime Day