The number of iPads you need depends on the size and complexity of your print shop.

Theoretically, multiple employees can share an iPad using their individual access codes. In the beginning, it may be sufficient to install a shared iPad at related stations. For example, employees in prepress, printing, finishing, logistics, and warehouse can share an iPad. 

However, you should provide a dedicated iPad for employees who do many different jobs simultaneously or in short succession to avoid unnecessary delays due to iPad switching and waiting for other employees.