Magic button mobile
Casting spells on mobile is tricky sometimes. Menu's are fairly small and alot of click action is set to take place on limited screen real estate.
Enter the 'magic casting overlay button'. If you cast magic spells on mobile, you'll see a button appear. Tapping that loads the magic spell again without going through the menu again (spellbook - find spell - tap spell - select target), but just lets you 'select spell - select target'.
While this is very convenient for combat magic (and PvP!), the button also shows for 'skill spells' like high level alchemy, enchanting jewelry. It's use is more limited there, as selecting from the spellbook automatically brings up the inventory, while the button version doesn't.