Character-pointer operators
Operator    Operation    Operand types    Result type    Example
+    pointer addition    character pointer, integer    character pointer    P + I
...

You can use the + and - operators to increment and decrement the offset of a character pointer. You can also use - to calculate the difference between the offsets of two character pointers. The following rules apply.

If I is an integer and P is a character pointer, then P + I adds I to the address given by P; that is, it returns a pointer to the address I
characters after P.

    p   : ^char;
    str : string[5];

begin
    str := 'abc';
    p := @str;
    p := p + 1; // <--

var
    p : PChar;
    str : string[50];
begin
    str := 'abcdefghigklmnoprstu';
    p := @str;
    p := p + 9; // <--
    ShowMessage(p^);

var
    p   : ^byte;
    arr : array[1..5] of byte;

begin
    // init arr
    // ...

    p := @arr;
    inc(p, 2);
    ShowMessage(IntToStr(p^)); // покажет трейтий элемент arr