WPA2 is currently the most secure type of Wifi/WLAN encryption.
To connect a device to an access point (AP), you use a WPA2 key or passphrase.
The key can be up to 64 chars hexadecimal or 63 chars alphanumeric + special chars.
There are many online key generators.
The problem is that they don't take into account mobile devices.
Entering 63-64 characters using a screen keyboard that you have to repeatedly switch between uppercase, lowercase, numbers and special characters is very tedious.
This generator lets you specify the maximum number of times to switch the screen keyboard.
The letter O and the number 0 are excluded to avoid confusion.
WARNING: Provided "as is". Use at your own risk. No warranties of any kind.