An authorizing committee writes the laws that create federal programs and give them permission to exist. The Appropriations Committees then decide how much money those programs actually get each year. Congress funds the government in those two separate steps, handled by different committees, and the difference explains a lot of what happens in Washington.
Authorize first, then appropriate
Think of it as permission, then money. The Armed Services Committees can authorize the Navy to build a new class of ship. The Agriculture Committees can authorize a rural broadband program. The Judiciary Committees can authorize a grant for local police. None of that moves a dollar. The program only operates at the size the appropriators fund, and the appropriators can fund it at less than the authorized level, or not at all.
Who the authorizing committees are
Nearly every standing committee in Congress other than Appropriations is an authorizing committee for its subject area: Armed Services, Agriculture, Judiciary, Energy and Commerce, Transportation, Veterans' Affairs, Education, and the rest. Each writes the policy for its corner of the government. The Appropriations Committee, split into twelve subcommittees, holds the purse strings for all of them.
Why the split matters
The two step design is deliberate. It keeps the people who design a program from also writing its check, and it gives Congress two separate moments to say no. It also creates a recurring fight. Authorizers set ambitious funding levels that appropriators cannot always meet, and programs whose authorizations have expired keep getting funded anyway, year after year, because the money, not the permission, is what keeps them alive.
Where the money side is tracked
Approps follows the appropriations half: where each of the twelve bills stands in both chambers on the tracker, every earmark written into them on the map, and the whole process from budget request to signed law on the process page.