iPhone

Can you connect your device to a wifi network?

Can you connect your device to a different Bluetooth accessory (i.e. BT headphones)?

Should be this case, contact your printer's support team and ask them.

Have you already read these support guides?

If you can't connect a Bluetooth accessory to your iPhone, iPad, or iPod touch - Apple Support

and/or

Connect to Wi-Fi on your iPhone, iPad, or iPod touch - Apple Support

Regards

Giulio

iOS doesn't support printing over Bluetooth.

https://support.apple.com/en-us/HT203343