How can i connect my iphone with jam speaker?

Since these are Bluetooth speakers, you have to “pair” them with your iPhone.

Turn Bluetooth ON in Settings, then follow the pairing instructions that came with the speakers. Each manufacturer uses different steps. If you dint have the printed manual, go to their support website and download the PDF version.

Follow the speaker's instructions to set it to Pairing or Discoverable mode, and then look for it in the iPhone bluetooth settings.

Set up and use third-party Bluetooth accessories - Apple Support