If you have claimed points for being single in your EOI for the 491 visa, you must stay single until you get your visa granted, not just until you receive the invitation. If you get married or enter a relationship before the grant, your points for being single may become invalid and this can risk your visa application.​ Even if your partner has skills assessment and English, unless they had these qualifications at the exact time of your invitation, you cannot switch your points category to claim partner skills you must have proved this right at the time of invitation, not later.​ After you get the 491 visa granted, you can add your partner later through a separate application, but it's important not to change your marital status before the grant to avoid issues with your main application.​ It's strongly recommended to speak to a migration agent if you are planning to marry before visa grant, so you don't risk your application.