I just bought a 1968 charger Hemi and didn't know it didn't have ps and pb. Can they be added?
As long as you have the room, you can get the parts you need at your local salvage yard.
You would need the pump, hoses, steering box, and you would need the pulleys for the crank and or water pump (depending on the routing of the belts) to accommodate the addition of the P/S pump.
A power brake booster would have to be added to the brake system.
Again as long as you have the room you can probably do the job.
If you don't have the confidence to do the job then your local automotive professional can get the parts and do the job.