Most automatic watches can be wound by hand. There are some exceptions, such as some Seikos.
Automatic watches have slipping mechanisms so that they cannot be overwound. Once an automatic watch is fully wound its mainspring will begin slipping, so no additional tension will be developed even though the crown is turned. There is no hard stopping point such as is found on manually-wound watches.
Automatic watches are designed for automatic winding and their gear ratios are correct for that function. That tends to make their hand-winding mechanisms a bit more delicate than manually-wound winding mechanisms, so it may not be a good idea to wind them by hand regularly.