What herbs? Some need a lot of space, some don't. You will need 18" to 24" pots with drainage holes and saucers for most herbs (one per pot). Small herbs like parsley and thyme can grow in 8"-10" pots with two or more plants per pot.

Growing indoors also presents a light challenge. There may be enough light in a south window in the summer, but likely there will not be enough light in any window in the winter. You may need to invest in an indoor grow light set up.

I much prefer to start seeds in plastic pots using a soilles mix which is sterile. Because your using a sterile mix that has no possible fungal bacteria it will help to reduce the possibility of damping off or other ailments seedlings usually get. Every herb has different requirements. Coriander and dill do not like being transplanted from small pots, but do fine if they are in close quarters like 5 seeds or so per 2x2 pots. Coriander and be planted even closer than that as its the broad leaves you want to harvest. Some herbs don't do as well as others indoors. You need to be more specific as to the herbs you want. There are virtally hundreds to choose from...