In all elections, members of the Independent Party of Oregon (IPO) get the same ballot as every other voter in Oregon, with this exception:

In the May primary election in even-numbered years, all registered voters receive the regular nonpartisan ballot, which contains all ballot measures and all contests for public office that are not run on a "partisan" (by party) basis.

Members of the major parties (Democratic and Republican) receive also a partisan ballot (paid for by state taxpayers), allowing them to nominate candidates to the general election. If you are not a member of one of those two parties, you do not get this ballot. The only public offices that are elected on a partisan basis in Oregon are:

U.S. President
U.S. Senator
U.S. Representative
Governor
Secretary of State
Attorney General
Treasurer
State Senator
State Representative
some county commissioners

Oregon does not require the major parties to open their primaries to anyone who is not a registered member of that party.

Minor parties in Oregon (such as the IPO, Pacific Green Party, Libertarian Party) are not allowed to have primary elections that are paid for by the state. Instead, they are required to nominate candidates by means of conventions or caucuses or other methods each party may devise.

The Independent Party is studying a system of secure electronic voting for its process to nominate candidates. To participate, you must register as a member of the IPO (see the link on the home page of this site).