If your employer uses Kivra to send pay slips, they will be sent automatically to your inbox. You don't need to do anything.
To ensure that you receive your pay slips, make sure you haven't paused your employer. Go to Settings > Senders > Letters to view all your active senders.
In some cases, you might not be able to receive your pay slip in Kivra. Many municipalities, regions, and government agencies instead send digital pay slips directly to your online bank, provided you have an account with Swedbank/Sparbanken or Nordea.