When more than one party is making a set of representations, it’s commonplace for drafters to use in the representations lead-in the couplet jointly and severally, as in “The Sellers jointly and severally represent to the Buyer … .”
One also sees jointly and severally and its adjectival counterpart, joint and several, used with obligations. For example, I’ve seen it recommended that in drafting indemnification provisions where there’s more than one indemnitor one either insert the phrase jointly and severally each time the indemnitors make a promise or state that “All of the Indemnitors’ promises in this Article are joint and several.”
But joint and several applies to liability. According to Black’s Law Dictionary, it means that a given liability can be apportioned equally among the members of a group or can instead, to a greater extent or entirely, be laid at the door of one or more select members of the group, at the discretion of whoever is apportioning the liability. To specify—presumably in an indemnification section—that certain parties are jointly and severally liable, all you need to say is “The Indemnitors shall jointly and severally indemnify the Indemnitees against … .” It’s unnecessary—in fact illogical—to seek to make other obligations, or representations, joint and several.