To connect a keyboard to an iPad, put the Bluetooth keyboard in pairing mode, open Settings → Bluetooth on the iPad, and tap the keyboard to pair. Once connected it reconnects automatically. Magnetic Smart Connector keyboards attach without any pairing at all.
Connection Methods
Bluetooth Pairing ⚡ Wireless
Turn on the keyboard and put it in pairing mode.
On the iPad, open Settings → Bluetooth.
Tap the keyboard under 'Other Devices'.
Type the pairing code if prompted, then press Return.