I would like to know what type of door furniture is suitable for an inward opening final fire door from a small office, about 6 people, thanks

Depends if you do not require security from people entering the office from outside. If people can enter from the outside then a standard single action lever door handle could be used in combination with a deadlock to be used when the office is unoccupied, opened by the first person in, and closed last person leaving. 

I you require security from people entering the office then a rim lock with a single action lever type thumb screw combined with a dead lock for security when the office is unoccupied. You could use a deadlock with a thumb screw lever on the inside and key access from the outside specially designed for the purpose like the Marston 4K Escape Mortice Dead Door Lock. Finally you could use a magnetic lock but quite expensive it all depends what you want.