Briefly describe voter registration

What will be an ideal response?

An ideal response would be:
Helping register sympathetic voters is important to candidates, parties, and interest groups. These efforts are typically aimed at citizens they anticipate will vote for their preferred candidate. Interest groups with active voter registration efforts include organized labor, business groups, and groups concerned about the environment and abortion.
Political parties favor laws requiring voters to disclose their party preference at the time they register. This requirement permits parties in states with closed primaries to limit participation to registered party members. Party registration also creates voter registration lists, which parties find extremely useful for campaigning and fund raising. List vending—selling voter lists with addresses, phone numbers, and party preferences—is a multimillion-dollar industry. Finally, voter registration helps the parties in the redistricting process because state legislators, using party registration, voting, and other data, can draw new congressional and state legislative district boundaries in ways that give their party an advantage.