Download Ilopad
This link always points at the newest release. It is a universal build, for both Apple silicon and Intel Macs:
Drag it to Applications
Open the downloaded .dmg. Drag Ilopad onto the Applications folder beside it, then eject the disk image.
Open Ilopad
Open Ilopad from your Applications folder. The first time, macOS asks if you are sure, because the app comes from the internet. Click Open.
Ilopad then explains what it needs. Click Grant Access.
Let macOS take you to the setting
macOS asks to confirm. Click Open System Settings, which opens the right page for you.
If you miss this dialog, you can get to the same place by hand: System Settings › Privacy & Security › Accessibility.
Turn Ilopad on
Find Ilopad in the list. The switch starts off:
Click the switch. macOS asks for your Mac password, because this changes a system setting. Type it and click Modify Settings.
The switch is now on. That is the whole permission:
Ilopad starts again
Ilopad closes its window and starts again by itself, so that it can use the permission you just gave. You do not have to do anything. Then its window opens.
Ilopad also has an icon in the menu bar, at the top right of your screen. When you close the window, Ilopad keeps running there. Click the icon to open the window again.
Pair your iPad or iPhone
In the Ilopad window, click + (or Add Device). Type a name for your iPad or iPhone and click Generate QR. Scan the code with the Ilopad app on it. Both have to be on the same network.
One more permission, only for pencil mode
Pencil mode shows your Mac screen on the iPad, so it needs Screen & System Audio Recording as well. Ilopad asks for it the first time you use pencil mode, and not before: an Ilopad window opens on your Mac. Click Open System Settings in it. That opens System Settings › Privacy & Security › Screen & System Audio Recording.
If Ilopad is in the list, switch it on. If it is not (macOS 15 does not let an app add itself), click + below the list, choose Ilopad in Applications and click Open. If macOS asks for your password, type it. Then macOS asks to quit Ilopad: click Quit & Reopen.
Uninstall
To remove Ilopad, with its settings and the permissions that it added, follow Uninstall on macOS.