Open Form in tabcontrol specifies

Create some form in which the form to be opened knows which tab it needs to select and then select it using TabControl.SelectedTab .

You can, for example, pass enum by parameter in the form constructor.

See:

public class Form1 : Form 
{
    public Form1(TipoTab tipoTab)
    {
        if(tipoTab == TipoTab.Cadastro)
        {
            tabControl1.SelectedTab = tabCadastro;
        }
        else
        {
            tanControl1.SelectedTab = tabConsulta;
        }
    }
}

public enum TipoTab
{
    Cadastro,
    Consulta
}

And use would be something like

public static void botaoCadastro_click(object sender, EventArgs e)
{
    var form = new Form(TipoTab.Cadastro);
    form.ShowDialog();
}

public static void botaoConsulta_click(object sender, EventArgs e)
{
    var form = new Form(TipoTab.Consulta);
    form.ShowDialog();
}