Tibetan is written in two families of hand, and the difference between them is visible at a glance.
Dbu can, the headed script, is the formal one. Each letter hangs from a horizontal stroke along the top, the head, and the letters are separated and upright. It is the script of woodblock printing, of inscriptions, of canonical texts and of anything meant to be read by strangers, and it is what a code chart and a font show by default.
Dbu med, the headless script, drops that top stroke. It is faster to write, it joins and abbreviates, and it exists in several distinct styles ranging from a careful book hand to a rapid cursive. It is the script of manuscripts, of correspondence, of notes and of much everyday writing, and a reader fluent in printed Tibetan may still need practice before a cursive letter or a manuscript colophon becomes legible.
The two are the same alphabet. The same thirty letters, the same four vowel signs, the same stacking rules and the same spelling; only the ductus differs. But the relationship is not quite that of print and handwriting in English, because the headless styles have their own conventions of abbreviation and ligature that the headed script does not use, and reading them is a skill acquired separately.
Both are encoded as the same characters, with the distinction left to the font.