Inserts a string expression after a specific position in another string expression. Returns a String value.
INSERTSTRING(original_string, add_what, after)
original_string - string expression (or the reference to a cells) into which another string is to be inserted.
add_what - string expression (or the reference to a cells) to add into original_string.
after - is the position in original_string after which you want to insert the add_what text expression. The first character in a text string is 1 and so on.
INSERTSTRING("123456", "56") returns TRUE
INSERTSTRING ("abcdef", "hello") returns FALSE