Most psalm superscriptions name a genre, mizmor, shir, maskil, or a musical direction, but Psalm 100's heading names an occasion, the todah, and that specificity sets it apart within the offering-related psalms. The todah is defined in the priestly legislation of Leviticus as a subtype of the peace offering brought specifically in thanksgiving, typically after deliverance from danger, illness or captivity, accompanied by loaves of bread that were themselves consumed in a communal meal rather than burned whole on the altar, which made the todah among the more social and celebratory of the Israelite sacrifices rather than one of the more solemn, atonement focused ones.
A psalm titled for this offering is naturally a psalm of pure praise rather than of request, since the todah itself is offered after the worshipper's need has already been met, not while it is still outstanding, and Psalm 100's content matches that logic exactly: it never asks for anything, moving instead directly to instruction, "make a joyful noise unto Jehovah, all ye lands," and to the stated grounds for gratitude, the LORD's goodness and enduring lovingkindness. This is what distinguishes an offering praise text from the more numerous offering petition texts found elsewhere in the same broad category, where the worshipper is asking the offering to be accepted or a request to be granted rather than simply giving thanks for a request already met.