I want to connect my phone to my iPad

What do you hope to achieve by connecting your phone (iPhone?) with your iPad?

If you are simply attempting to access your mobile phone hotspot, this support page should provide the information that you’ll need for your iPad:

If Personal Hotspot is not working on your iPhone or iPad (Wi-Fi + Cellular) - Apple Support

A wired-connection between an iPhone and hotspot will allow the iPhone to share its hotspot connection with the iPad without using WiFi/Bluetooth. Some iPad Pro models with a USB-C port can also charge a connected iPhone. A wired-connection between iPad and iPhone provides no other useful function.

If you have an iPad and iPhone - and wish to send/receive SMS/MMS messages via your iPhone, ensure that devices are signed-in to iCloud with the same AppleID; to send SMS/MMS messages (green bubbles) from your iPad, you must explicitly enable Text Message Forwarding for your iPad on your iPhone...

On your iPhone:

Settings > Messages > Text Message Forwarding - set to ON - and explicitly enable your iPad from the list of devices.

Also ensure that Messages in iCloud is enabled on both your iPhone and iPad:

Settings > [Your Name / AppleID] > Messages - set to ON

Additional information can be found here:

Forward SMS/MMS text messages from your iPhone to your Mac or iPad - Apple Support

To accomplish what purose, exactly?

iOS/iPadOS device cannot just be connected by Bluetooth.

If you are wanting to connect your iPad to use a remote device to answer and place calls to your iPhone or send/recieve SMS messages, there are procedures to do just that.

Tap and read these links below.

Make and receive phone calls on iPad - Apple Support

Set up Messages on iPad - Apple Support

What is the difference between iMessage and SMS/MMS? - Apple Support

Forward SMS/MMS text messages from your iPhone to your Mac or iPad - Apple Support

Good Luck to You!