To stuff a balloon:
To stuff at home with out a balloon stuffer: You can use a funnel or a funnel made from rolling a piece of paper or card for small items. Or you can use a balloon stretcher tool I have one I got off ebay which is sold as a ”ELASTRATOR Castrating PLIERS” its a tool used in veterinary surgery but is also the perfect tool to open up balloon ends and stuff.
Or of course you can use a balloon stuffer if you are wishing to stuff with larger things, there are ways of making a DIY stuffer if you search online.
To blow up balloon:
Like with any balloon you inflate with a balloon pump.
You can blow by mouth however you may get some condensation doing it via mouth so I recommend a balloon pump.
You can also use a electric pump or helium tank depending on what effect you are after.