WHOLE CHARACTER
务wù
a matter; an affair; a duty (事务,任务); to engage in; to devote oneself to (务工,务农); must; without fail (务必,务须)
务 is work and duty: 任务 'task', 义务 'duty', 务必 'make sure to'.
The header drops the sound-side name (从力、声); the detail section says the old full form 務 carried the sound (wù). The simplified top 夂 is a written remnant, and 力 is the meaning side.
TOP: A BENT WRITTEN PIECE — REMNANT OF THE OLD SOUND SIDE
夂zhǐ
a bound 'follow/go' graph (dictionary radical)
A bound piece that appears at the top or bottom of several characters; not a standalone modern word.
In 务: top: a bent written piece — remnant of the old sound side A written piece, not a standalone word here.
MEANING: THE STRENGTH SIDE (ZDIC 从力)
力lì
force; strength
Standalone meaning is kept separate from its role in other characters.
In 务: meaning: the strength side (ZDIC 从力) Shown with its documented or clearly limited role.