Azkaban.
Digitalis is not a spell in Harry Potter.
No
Harry Potter's favorite spell was Expelliarmus (disarming spell) but he also used Stupefy (stunning spell) a lot.
no
The prison is named Azkaban.
Harry Potter doesn't use a spell to fly, he flies using an enchanted broomstick.
There is no weak spell in Harry Potter. It is only weak if they caster of the spell is weak. When you cast a spell say it loud and clear.
the spell is a charm
Harry Potter and the Deathly Hallows Part 2 (the 8th one)
Azkaban is not a person, it is a prison.
Alohomora
Protego.