To enable SMS in your account, navigate to Settings and once the page loads, select Integration. Click on the Add Integration button on the top of the page.
In the window that appears click on SMS.
Simply choose your SMS Company and follow the setup instructions for the chosen provider that appear on the right hand side of the window. The instructions that appear on the right hand side will also include the settings needed to enable two-way SMS in Elvanto.
Once enabled, send yourself a test message to ensure everything is working as expected.