Below is a step-by-step breakdown of how to obtain and install the classic Visio desktop client. The desktop app is not free. You need one of the following:
Microsoft Visio is the industry-leading diagramming and vector graphics application. While a web-based version exists (Visio for the web), the Visio desktop application (Visio Plan 2) provides the full feature set, including advanced charts, stencils, and automation tools. visio download desktop
Before installing make sure to follow these steps given below
Make sure you have backed up your device using iCloud or iTunes on your PC or Mac. Otherwise, you may lose your data.
You can connect your device using a Lightning or USB-C cable to your PC or Mac.
On your device, go to Settings - [your name] Find My - Find My iPhone/iPad, then turn off the Find My iPhone/iPad.
In iTunes or Finder (Mac), hold down the Shift key (or the Options key on a Mac) and click on Restore iPhone... button.
After iTunes has installed the .ipsw file on your device, follow the on-screen instructions to restore your data.