Oregon doesn’t require a license to become a process server. Any individual, age eighteen or older, who is not a party to the case, may serve civil process in Oregon.
Take a look at Rule 7 from the Oregon Rules of Civil Procedure:
E. By Whom Served; Compensation.
A summons may be served by any competent person 18 years of age or older who is a resident of the state where service is made or of this state and is not a party to the action nor, except as provided in ORS 180.260, an officer, director, or employee of, nor attorney for, any party, corporate or otherwise. However, service pursuant to subparagraph D(2)(d)(i) of this rule may be made by an attorney for any party. Compensation to a sheriff or a sheriff’s deputy in this state who serves a summons shall be prescribed by statute or rule. If any other person serves the summons, a reasonable fee may be paid for service. This compensation shall be part of disbursements and shall be recovered as provided in Rule 68.