You will need a range of sizes of fishing hooks so that you can fish a variety of fishing situations and use different baits.
Experienced anglers, especially match anglers, tie their own hooks to lengths of line ready for fishing, but you may find it easier to buy the ready-tied kind if you are just starting out. This avoids you needing to buy several spools of line for hooklengths as well as the hooks, so it probably isn’t any more expensive.
A good range of hooks to carry would be in sizes from 20 for the smallest fish, with small baits such as maggots, up to size 8 for larger baits such as luncheon meat or large lobworms for catching larger fish such as carp.
Sizes from most manufacturers go up in even numbers, so for the range suggested, you would have a total of 7 sizes, i.e. 20, 18, 16, 14,12,10 and 8.
Barbless hooks work just as well as barbed hooks, some say better, for most situations, and for beginners and children they are definitely easier to use. If you are thinking of using barbed hooks, check that you are allowed to use them where you intend to fish, as many waters do not allow them.