Cargo bikes and children work together incredibly well. If you have a box bike you can easily secure a special car seat, but ensure that it is compatible by checking with the brand of cargo seat first.
Babboe cargo bikes have been specially designed to accommodate a special baby seat or a Maxi-Cosi carrier, which will allow you to ride with your baby from around three months old.
As your child gets older. You can swap chairs and safety harness as they grow.
I’ve been happily riding around with my tall eight year old in all designs without the use of harness protection. This is entirely a personal choice and, if they aren’t within your line of sight, e.g. on a longtail e-cargo bike, there has to be a lot of trust between you around keeping reasonably still, and not flailing arms and legs around.
In terms of age limit, it becomes a case of weight limit and where the rider will sit and many of the best electric cargo bikes are designed for adult passengers too.
However, there are age minimums in terms of actually riding any electric bike, with most countries ranging between the age of 14 to 16 years.
In the USA, the exact age minimum is on a state by state bases, and varies between the aforementioned age range above.
In the UK, there is a blanket age minimum of 14 years old.