A sponsor or patron is a person, usually a legislator, who presents a bill or resolution for consideration. Those who support it are known as cosponsors or copatrons.
Sponsor (legislative) Wikipedia
A sponsor in the United States Congress is the first member of the House or Senate to be listed among the potentially numerous lawmakers who introduce a bill for consideration. Committees are occasionally identified as sponsors of legislation as well. A sponsor is also sometimes called a "primary sponsor."
It should not be assumed that a bill's sponsor actually drafted it. The bill may have been drafted by a staff member, by an interest group, or by others. In the Senate, multiple sponsorship of a bill is permitted.
In contrast to a sponsor, a "cosponsor" is a senator or representative who adds his or her name as a supporter to the sponsor's bill. An "initial cosponsor" or "original cosponsor" is a senator or representative who was listed as a cosponsor at the time of a bill's introduction, rather than added as a cosponsor later on. A cosponsor added later is known as an "additional cosponsor". Some bills have hundreds of cosponsors.