Along with the title, lines 1-3 establish the poem's premise, or conceit: The speaker is a consumer filling out "A Consumer's Report," or review of a product they've "tested." As line 1 establishes, that product "is Life" itself! (A few actual products carry the brand name "Life," including Life cereal and Life magazine, but the poem goes on to establish, through context, that it's talking about life as in human existence. Some of its descriptions wouldn't make sense if applied to the cereal or the magazine; they could only apply to something much broader.)
Having tested this "product"—at least, for a certain number of years—the consumer is now offering their assessment in response to some sort of market research survey. Who could be conducting such a survey on behalf of life itself? The poem, mischievously, leaves this question unresolved. The consumer says that "I have completed the form you sent me," but "you" is never identified, nor is the nature of the "form" specified. The poem's premise is based on real-life market research involving consumer tests and reviews, but the equivalent process for something as cosmic as "Life" is left to the imagination. The speaker acknowledges that their "answers are confidential"—perhaps a joke about the private nature of one's inner communications with the universe, God, etc.
Basically, these first lines set up an extended metaphor comparing life to a consumer product. This metaphor carries throughout the poem, as the poet explores the premise in depth. Although life isn't a product, the poem invites readers to consider what the two things have in common—and how they themselves might review life if they had the chance. (Do they find life satisfying? Easy to manage? And so on.) The poem also satirizes the kind of hyper-capitalist society that treats everything as a product, even the most profound experiences imaginable.
As a parody of real-life consumer reviews, the poem's style is flat and prose-like. Its free verse sounds slightly dashed off, as if the consumer were casually jumping from one opinion to the next. Note that the speaker here is separate from the poet; the poem adopts this jaded consumer's voice in a variation on the dramatic monologue.