Hot air balloons are incredibly versatile and can travel at a different height.
It depends on air temperature and wind conditions.
Hot air balloon baskets are designed for everyone to have enough space to stand comfortably and enjoy an unobstructed view over the basket.

The takeoff is usually very smooth and quiet. One the most impressive moments is when you see the balloon lifting from the floor, especially for people who suffer from vertigo, but the lack of movement in the basket and the fact that there is no physical link between the balloon and the ground makes the sensation of airsickness disappear and therefore the flight more enjoyable.

Hot air balloon baskets vary in size and passenger capacity.
The operating company needs to know the bodyweight of all passengers to plan the load. There may be no weight restriction as such per passenger but per basket, and you will be asked to inform if anyone in your party is over 100 kg.
This does not mean they will not be able to travel. 

The age limit for hot air ballooning is flexible. Usually, there is no upper limit as long as you are fit enough to climb into the basket using unique footholds on the side of the basket.
Your pilot will show you how to do it.  All travelers need to stand in the basket for one hour and maybe absorb a small bump when landing. Therefore all passengers need to be able-bodied and have no injuries, chronic knee or back problems. Hot air ballooning is also not suitable for pregnant ladies.

As a rule, there is no strict lower age limit for children, but it is for you to consider if your children will enjoy their ride. Children under 120 cm tall (3,94feet) will have a restricted view over the top of the basket if any at all.
Also, gas burners make a characteristic loud noise that usually scares children as young as 5 or 7.

Passengers are recommended to wear comfortable clothes and footwear, as hot air balloons usually take off and land in the countryside, on the farming land.
So passengers are advised to choose their clothes and shoes accordingly.