。
Daily exercise is essential for good health.
Literal
Every-day [possessive-の] exercise [subject-が] health [for-には] indispensable [copula-である].
不可欠 ('indispensable') is a formal Sino-Japanese compound — 不 (not) + 可 (able) + 欠 (lack) = 'cannot be lacking.' には marks health as the beneficiary or required-for context. Marking 運動 with が (subject) rather than は (topic) presents the claim as an assertion of fact rather than a comment about exercise — a small but consequential particle choice in formal writing.