Students sometimes will be provided handouts of pinyin, Chinese characters, numbers etc. for each lesson. 
 But most of the time, I share materials in class and students can take notes. 
No books are required. 
However they need a notebook, pencils, crayons, (or if you prefer a copy of Chinese character writing practice book for class. You can order online. 田字格) 
We often draw pictures to go with their weekly lesson. It's a good idea to always have art supplies like crayons, a sketch book/or copy papers, markers/or coloring papers, glue, and scissors available. 

Learners will not need to use any apps or websites beyond the standard Outschool tools.