The writing system J.R.R. Tolkien created for languages including Quenya is Tengwar.
Tengwar, also called the Fëanorian characters, is an artificial script used in Tolkien’s mythology. The Elf Fëanor is credited within the fictional history with devising it, while Tolkien developed its detailed forms, sound values, and usage for his constructed languages.
Tengwar is an abugida-like writing system: consonant signs carry vowels through attached marks called tehtar in many modes. Its exact values vary according to the language and mode being written, so Tengwar is not simply an alphabet with one fixed pronunciation.
Tolkien also created other scripts. Cirth is a separate runic system associated especially with Dwarves, while Sarati is an earlier script attributed to Rúmil. These names are sometimes mixed up because Tolkien’s languages and scripts developed across a large, interconnected body of notes.