Code:
private void button1_Click(object sender, System.EventArgs e){
            

string accessPath = Application.StartupPath.ToString() + "/test.mdb";

string connectionString = "provider=Microsoft.JET.OLEDB.4.0; " + "data source ="
+ accessPath + "; Integrated Security=SSPI;";

string commandString = "INSERT INTO tabelaTest VALUES ('" + txtBoxBla.Text + "')";
OleDbConnection AccessDbConnection = new OleDbConnection(connectionString);
            OleDbCommand AccessOleCommand = new OleDbCommand(commandString);
            AccessDbConnection.Open();
            AccessOleCommand.ExecuteNonQuery();
            AccessDbConnection.Close();
            
           
}