This character is a Other Letter and is mainly used in the Katakana script.
The glyph is not a composition. Its East Asian Width is wide. In bidirectional text it is written from left to right. When changing direction it is not mirrored. This katakana joins with other adjacent katakana to form a word. U+30CF offers a line break opportunity at its position, except in some numeric contexts. The glyph can be confused with one other glyph.
The Wikipedia has the following information about this codepoint:
Ha (hiragana: は, katakana: ハ) is one of the Japanese kana, each of which represent one mora. Both represent [ha]. They are also used as a grammatical particle (in such cases, they denote [wa], including in the greeting "kon'nichiwa") and serve as the topic marker of the sentence. は originates from 波 and ハ from 八.
In the Sakhalin dialect of the Ainu language, the katakana ハ can be written as small ㇵ to represent a final h sound after an a sound (アㇵ ah). This, along with other extended katakana, was developed by Japanese linguists to represent sounds in Ainu not present in standard Japanese katakana.
When used as a particle, は is pronounced as わ [wa]. は is also pronounced as わ in some words (e.g. もののあはれ pronounced as mono no aware).