How can I use multiple windows with PDFpen for iPad & iPhone?
PDFpen 5 or higher supports multiple windows on iPadOS 13 or higher. Multiple windows is currently unavailable on the iPhone. View two documents at once with PDFpen, or use PDFpen and another app such as Safari, Mail, or Messages simultaneously.
To turn Multitasking features on or off, go to Settings > General > Multitasking & Dock.
To open a second document in PDFpen for iPad & iPhone, drag PDFpen out of the Dock to make a Slide Over or drag it to the right or left edge of the screen to make a Split View.