From a long-running ad for Tinkham Cycles found in Bicycling World and several other publications of the day - Load-carrying cycles, usually tricycles, appeared early on in the development of the safety bicycle, and came in an assortment of styles.
This style of cargo cycle - the tadpole trike, as it is known now, rapidly became the dominant design. This particular one, a Racycle, advertises its "changeable gear".
An ad for another tadpole trike, this one a Cataract - warning other makers against patent infringements - a common (and quite vague) threat in the bicycle boom. This one, like the Racycle above, has a normal (if extended) headtube, and steers with handlebars much like a normal bicycle.
From the 1899 Tinkham Cycles catalogue. Not the detachable cart section, which is useable alone as a puchcart. This bike also came in a variation with a wheelchair instead of the cart section.
This postcard, from around 1906, of a French baker and his triporteur (and some huge loaves of bread...) illustrates the type of cargo trike common throughout french cities well into the 30s - the same ones used in the annual triporteur races.
2 styles of "porteur" available in the mid-30s - the lighter, faster, "paris" style of the newspaper couriers, and the "boucher" style of shop deliery people.
From a 1938 French cycle supply catalogue, this type of cycle is a basic example again of the "triporteur" common as a baker's or other delivery bike throughout France and Europe..
The traditional "butcher"-style 20" front wheel porteur for shop delivery people was still popular up through the 50s and later in france (and the uk as well)
A Daniel Rebour drawing of a French "porteur" bicycle, of the type produced by both Rene Herse and Alex Singer, among others. This is a high-zoot version of the bikes ridden by French newspaper couriers.
Dutch Bakfietsen. Though these pictures were taken in the 1970s, they illustrate a bike which developed much earlier, and is still in common usage in cities like Amsterdam for carrying loads of every possible description.