OLYMPIA — Washington residents will be able to start the process of buying insurance through the state’s health-care exchange next month, but many likely still have questions about their insurance options.

A Spokane-based toll-free customer-support line will start taking calls at 1-855-923-4633 at 7:30 a.m. Tuesday, and potential customers will have a live person to talk with about plan choices, costs and what kind of subsidies they might be eligible for.

The call center, which will be staffed by 80 people, will be open from 7:30 a.m. to 8 p.m. Monday through Friday.

The state’s open-enrollment period for purchasing insurance through the exchange starts Oct. 1 for coverage that takes effect on Jan. 1.

The plans that will be part of the exchange are expected to be voted on by the Washington Health Benefit Exchange Board this week.

Six insurance companies have been approved to join the exchange, and three others have been rejected because their plans didn’t fit all the federal rules.

Insurance Commissioner Mike Kreidler last month approved plans from Bridge-­ span, Group Health Cooperative, Premera Blue Cross and LifeWise, a subsidiary of Premera. Proposals from Community Health Plan of Washington and Kaiser Foundation Health Plan of the Northwest were approved Friday.

Molina Healthcare of Washington and Coordinated Care Corporation have appealed rejection of their proposals. Moda Health Plan did not appeal its exclusion from the exchange.

Only insurance companies approved by the upcoming vote will be able to offer individual health insurance through Washington’s exchange during the open-enrollment period, between Oct. 1 and March 31, 2014.

Other companies will have to wait until next year, during the second enrollment, Oct. 15 through Dec. 7, 2014.

“Everything is falling into place for us to be ready for opening our doors” for the October enrollment period, said Michael Marchand, spokesman for the exchange.

An estimated 1 million Washington residents — or about 1 in 7 — are uninsured. Officials don’t know the total number who might buy health insurance through the exchange, but the Insurance Commissioner’s Office expects an estimated 328,000 people in Washington to benefit from the expansion in Medicaid coverage.

Under the plans preliminarily approved by Kreidler and awaiting a final vote by the Washington Health Benefit Exchange board, rates vary based on factors like age, home county, smoking habits and choice of plan.

Under the federal health-care law, annual out-of-pocket costs, including deductibles and co-pays, are capped at $6,350 for an individual and $12,700 for a family.

Marchand said the call center is expecting high volumes at the start of the enrollment period. Overflow calls and language assistance for non-English speakers will be handled out of a call center in Virginia, he said.

“A lot of people will probably have very basic questions on the cost and coverage, as well as the convenience — ‘Can I keep my doctor?’ ” Marchand said. “It will all be unique to their individual situation.”