Yes you can put a bottle of fuel injector cleaner into an entire tank full of gasoline which is actually what is recommended.
You can put the fuel injector cleaner in the gasoline tank when the tank is near empty or half full and then pump the rest of the gasoline into gas tank to fill it up.
Then run the engine for around 5 or 10 minutes to allow the fuel injector cleaner to work it's way through the fuel system and through the fuel injectors.
After 5 or 10 minutes if idling or driving the vehicle the fuel injectors should be cleaner and the engine should run much better than before.
However if the fuel injectors are really dirty or clogged then you might need to have the fuel injectors cleaned professionally.