How to scramble text with items in vanilla Minecraft?

Judging from the title of the question, it seems that you want to add the "magic" effect on an item name by renaming it via an Anvil.

However, it is impossible to input the § symbol in an Anvil. In-game, the symbol can only be used in Book & Quills, as well as the chat box. Therefore, you cannot legitimately format item names with an Anvil in Vanilla.

Moreover, note that l is used to bold text while k is used to scramble. &llll or §llll will produce lll only. For future reference, you can visit the Minecraft wiki page for Formatting codes.

Actually, it is possible to put the § symbol. If you go to the keyboard languages and scroll down to the “symbols” one, you are able to type that special character. This will only work on devices with a mobile keypad, or a keypad with special symbols, and will not work with copy and paste.