In the underground
Use the itemfinder at the spot where mr fuji once stood at the top of Pokemon tower you should dig up a soothe bell. where mr fuji was standing use your itemfinder there
well, there are tons of items, the main items are spheres (those let you buy things), fossils (you can go to oreburg and turn those fossils into other pokemon), and many many more.
You can't grow berries in Leafgreen, so get 6 meowth. (Pickup ability) battle low-level Pokemon, checking the party every now and then. If they don't have items already, Meowth have a chance of obtaining a berry for you after each battle.
Items cannot be buried, you simply cannot see them with the pixel eye. You need to use a special machine called a Dowsing Machine (or sumin like tht).
Pokemon can't dig up items, but there are Pokemon with a special ability which makes them able of finding an item after a battle there is a 10% chance. This ability is called pick-up. These Pokemon are: aipom, zigzagoon, linoon, munchlax, phanpy, teddyursa and meowth.
In the underground
u can only get the other items not orbs
you trade them to hikers that are underground for an assortment of items.
mostly berries but they can also pick up rare candy pp up and very rarely a nugget
you train them!!!
Use the itemfinder at the spot where mr fuji once stood at the top of Pokemon tower you should dig up a soothe bell. where mr fuji was standing use your itemfinder there
Level them up, Use items on them like Protein, Full Restore, Iron, Carbos, Hp up, Calcium, PP up, Zinc, have them hold soothe bell in battle.
You can dig up fossils underground by using the Explorer Kit in the Key items pocket of your bag :)
Level them up.
well that depends on your badges and the items you have but oh ho can show up anywhere throughout your journey
well, there are tons of items, the main items are spheres (those let you buy things), fossils (you can go to oreburg and turn those fossils into other pokemon), and many many more.