J.R.R. Tolkien’s invented writing system used for Quenya was Tengwar.
Tengwar is a script created by Tolkien for writing several of his fictional languages, including Quenya. The word is commonly translated as “letters” or “signs” in Quenya. Tolkien designed the script with elegant, adaptable letter forms and developed different modes for representing different languages.
The script appears in Tolkien’s stories and illustrations, most famously in the inscription on the One Ring. That inscription is written in Tengwar, although the language of the words is Black Speech rather than Quenya. This distinction is a frequent source of confusion.
Cirth is another Tolkien writing system, characterized by angular runes and associated especially with Dwarves. Sarati is an earlier script in Tolkien’s invented writing history. Tengwar therefore identifies the script, while Quenya identifies one of the languages it can represent.