There is several types of fillers used by the packaging machine industry, these listed below are the most common.
Auger/Agitator Filling Machines: designed to fill dry mixes, such as flour and sugar. The fillers have a hopper shaped like a cone that holds the mix and puts it in a pouch using an auger screw that is controlled by the agitator. The mix is filled in a pouch that is made of paper or poly that is formed in a collar and the pouch gets sealed by a series of heaters and dies.
Flow filling machines: designed for liquids, oils, and thin food products. These fillers are designed when they fill a bottle or tub that enters the machine, the ejects the open bottle back onto another conveyor for sealing.
Tablet fillers: These are designed for products that is counted by pieces instead of weight. These are designed for small bottles similar to some of the flow fillers, but the hopper of the filler is set up to permit scan counting of tablets or candy pieces.