Pizza boxes are made from corrugated cardboard.
When is it recycled?
All clean Pizza boxes, like clean corrugated cardboards, are recycled.
When is it not recycled?
When the box is soiled.
Grease is hydrophobic, i.e. it does not mix with water. When the grease content reaches 20% of the box's mass, the grease will start to interfere with the fibre bondings and greatly reduce the paper strength of the end product.
Ask the shop to put a wax paper underneath the pizza, that way you can enjoy your pizza, throw your clean pizza box in the recycling bin and only throw the wax paper away.
Ask the shop to cut up your pizza and package it in your container.
Compost the soiled parts that will not be accepted for recycling.
How to recycle?
As long as the top part of the pizza box is still clean, tear it off, it will be accepted for recycling.
Also flatten and put all your other cardboards from your online deliveries, etc., into your recycling bag.