CODE EXAMPLE FOR SQL

insert sql

-- sql insert using string format 

        -- you dont need to do this unless you want to specify what
                  --    columns you want to insert
                                 ⬇️
String = "INSERT INTO Marcas (yourcolumn) VALUES(if your value is string use 'your string' and if is a number you dont use the '')";

-- exemple:     
                                                -- because my idcostumer just allows numbers   and that is a text one and i use the ''                                    
                                                         --    and i dont use the ''
                                                                          ⬇️                             ⬇️  
ssql = "INSERT INTO Costumer (idcostumer, costumername) VALUES("textboxidcostumer.Text + ", '" + textboxname.Text + "')";