DC supply voltage in op amps and instrumentation amplifiers
Yes, you will need to provide power supplies to any op-amp or in-amp in your circuit if you want them to act like op-amps and in-amps.

You can see in the datasheet (INA118 shown) this is specified in the "recommended operating conditions" table:


Most of the other specifications in the datasheet are only valid if you are operating the chip according to the recommended operating conditions.