First you have to decide what you mean by catering. Without the constraints of a definition it is hard to determine what you need on any level, material or financial. Ask yourself the questions: What kind(s) of food? For up to how many people? Cooked on- or off-site or both?
Make a trip to your county's health department and ask for their guidelines/requirements/codes for approval/licensing. Ask if surrounding counties adhere to the same codes. Peruse that info.
Many counties disallow using a home kitchen for a commercial venture (which means you cannot cook at home for sale on- or off-premises); those that allow it most always require the kitchen to be inspected/approved before licensing (so get those requirements, if so--and find out from the zoning department if
they'll have an issue with it and/or if you'll need zoning approval or a variance).
In most places you do not need HD licensing if you cook for a client in their home but you might need a county business license, depending on your county. In some counties, if you bring your own kitchen/cooking apparatus (like mobile kitchens, barbecue set-ups on trailers, etc.), you can forgo HD licensing as long as the cooking occurs on a client's private property. Others disallow this without inspection/approval of the apparatus. There's more to this part of it--just get to your county's HD and see what's what.
There are some books and web sites that might be helpful (search Amazon and use Google) but none that are all that comprehensive, imo. This is less an issue with the material, rather it is simply because catering has so many variables specific to the caterer, many specific to the county/area, many to the type of clientele desired, that it would be quite difficult to cover all the details of every possible combination of variables. Still, there is useful information out there; you just have to collect it and piece it together.
Many if not most caterers start small, under the radar, without HD or licensing involvement, by doing smaller parties/events for family and friends (often charging nothing but the cost of food, in the beginning). This gives an individual a good idea of the vagaries and nuances of this type of work. Soon after, they start charging 'real money' for their services, most of which goes for food and building of their equipment inventory. Later, they go 'legit'. (I do know several caterers who, because of strict area codes, have never gone legit.)
Many people start out with limited offerings--barbecue, appetizers, kid's parties, holiday spreads--and only expand when they feel up to it or as demand increases. Some just flesh out the offerings within their purview and leave well enough alone. Much depends on the caterer and the market in which s/he operates.
One is only limited by one's imagination and we all have different imaginations and desires. I used to cater from restaurants years ago, which was okay, but since have cooked privately (cooking only in a client's home as opposed to cooking off-site--I don't have a choice in this anyway as 90% of my jobs are hundreds of miles from where I live). I cook pretty much whatever I want--food from a variety of cuisines and styles, pretty much for people who appreciate good food and what goes into it, and for whom my fees aren't much of a concern. This works for me well, it's not my primary income source, but were I home all the time it's likely I'd pursue a restaurant instead as I much prefer it. Others work in different ways, cooking privately or catering, expansive offerings or limited (there are several successful barbecue caterers that are members here), full time or just a sideline.
So, doubtful that my ramblings have helped much but if you can define what path you're thinking of...(you can always change it, add to it, subtract from it at any time
)
