Wideband o2 sensor vs narrow band o2 sensor

How I know and identify if my car has wideband or narrowband o2 sensor? If has narrowband sensors, is that easy to replace it with wideband? Or do I need to make some modifications on the ecu and wiring to be able for tuning?

There are wideband controllers (like the Innovate LC-2) that have two outputs. One can be programmed to output voltage like a narrowband sensor, and the other can provide wideband output (for a gauge, logger, dyno, etc).

Now if you are using an aftermarket ECU (plug-in or stand-alone), you might just change the sensor & wiring, and configure the ECU to know you have a wideband sensor.

Sound good very clear, also one more query. For the old model vehicle like jeep xj 94 which has an obd1 port to connect ECU, what software and hardware I need to be able to access ECU to reflash the data? Do I need portable wideband o2 sensor in case I use unichip interface device?

Ha! Back then we only dreamed of Flash memory. For something of that vintage, you generally had to burn PROMs (Programmable Read Only Memory), later we had EPROMS (Erasable PROMs). Replacing it with a modern standalone ECU would be a better project.