The effort by political candidates and their staff to win backing and support by voters in the quest for political office is known as

The effort by political candidates and their staff to win backing and support by voters in the quest for political office is known as a campaign. 
These campaigns, where presidential candidates are trying to find support of voters by promoting themselves via advertisements on TV, the Internet, newspapers, etc. can last for months before the actual elections. People are constantly bombarded by messages about these candidates so as to vote for them when the elections come.