This character is a Other Letter and is mainly used in the Arabic script.
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it is written as Arabic letter from right to left. When changing direction it is not mirrored. The word that U+0637 forms with similar adjacent characters prevents a line break inside it. The glyph can be confused with 23 other glyphs.
The Wikipedia has the following information about this codepoint:
Teth, also written as Ṭēth or Tet, is the ninth letter of the Semitic abjads, including Phoenician ṭēt 𐤈, Hebrew
ṭēt ט, Aramaic ṭēṯ 𐡈, Syriac ṭēṯ ܛ, and Arabic ṭāʾ ط. It is the 16th letter of the modern Arabic alphabet. The Persian ṭa is pronounced as a hard "t" sound and is the 19th letter in the modern Persian alphabet. The Phoenician letter also gave rise to the Greek theta (Θ), originally an aspirated voiceless dental stop but now used for the voiceless dental fricative. The Arabic letter (ط) is sometimes transliterated as Tah in English, for example in Arabic script in Unicode.
The sound value of Teth is /tˤ/, one of the Semitic emphatic consonants.