WASHINGTON — House Democrats are unveiling their first bill for the new Congress, a good-government package to limit big money in politics, make it easier for citizens to vote and require presidents to disclose their tax returns.

The legislation, H.R. 1, sets the tone for Democrats as they take the majority in January.

The bill would create national voter registration and expand access to early, online voting. It also would increase federal support for state voter systems, including paper ballots to prevent fraud.