If you are an employee that receives salary, you need to be registered for A-tax. The same applies if you are receiving pension payments. Being registered for A-tax enables your payer to deduct preliminary income tax from you salary or pension. On your A-tax certificate, you can find which tax table that your payer should use when they calculate how much preliminary tax to deduct from your salary.
The opening hours for the e-services are seen in the white box next to the yellow log-in button. If the the e-service is closed you see the text "Stängd" in the white box.
If your employer asks about your tax table, you can provide them with your A-tax certificate. On the e-service Mina sidor (My pages), you can view, print or download a PDF version of it.
If you only have one payer, you can use the e-service Räkna ut inkomst efter skatt och se skattetabell (Calculate income after tax and consult tax table) to calculate your income per month after tax deductions. You can also find your current tax table.