If you are either in a married or de-facto relationship with an Australia PR/Australian citizen, you may have the eligibility to obtain a partner visa. In case you are living offshore, you would have to apply for the offshore category under Subclass 100/309. Your visa application will be assessed at the processing center that’s nearest to you.
If you are currently residing in Australia with your Australian partner, then you would apply for the onshore category under the subclass 801/820. For the Partner Visa, processing times vary significantly. You may also have the eligibility for a Prospective Marriage Visa in case you are residing offshore and engaged to be married to an Australia PR/Australian citizen as well.