Arabic letter beh (isolated form)

It is a display form of beh, not a separate letter. The base character ب is used in ordinary Arabic text; a shaping engine selects the isolated, initial, medial, or final glyph from neighboring letters. ﺏ stores the isolated shape directly, so it is suited to legacy conversion or glyph display, not new Arabic writing.

Arabic writing developed gradually from Nabataean Aramaic, though the transition is not fully reconstructed. Dated Arabic-script inscriptions with a full Arabic letter repertoire appear in the late fifth century CE, including one dated 470 CE. Beh served as a consonant in an abjad, a writing system that primarily records consonants.

Naskh was used for correspondence and documents; Kufic appeared in Qur’anic manuscripts, inscriptions, and coins. Persian calligraphic traditions developed their own styles. These are writing and artistic contexts, not new meanings for beh.

what does ﺏ mean when someone sends it?

Read it as a letter sample or fragment. Alone, ﺏ identifies beh but cannot tell you which word was intended. It may be a typeface example, a text fragment, or a compatibility problem in converted data.