There is in most cases some time between the signing of the contract and the closing date of the deal. A normal amount of time is three months but this can be negotiated. Observe that the time between signing and closing can never be more than two years due to Swedish property law.
When the purchase is paid in full the buyer will receive the keys to the house and the real estate agent will make sure that all of the seller´s mortgages are removed from the property.
Once the contract is signed and the purchase price is paid, you will need to register the property with the Swedish Land Registry (Lantmäteriet). This will transfer ownership of the property to you and ensure that you have legal title to the property. This process is normally done by the buyer’s bank but the service can also be provided by the real estate agent.
Note that when you buy property in Sweden you have to pay a tax (stamp duty) of 1,5 % of the purchase price plus 825 SEK in expedition cost. If you want to buy through a company the tax is 4,25 % plus 825 SEK expedition cost.