In OCaml, you can use the Printf module to format strings. Here is an example:

let name = "John"
let age = 30
let height = 180.5

let formatted_string = Printf.sprintf "Name: %s, Age: %d, Height: %.1f" name age height

(* The value of formatted_string is now: "Name: John, Age: 30, Height: 180.5" *)

In this example, we use the Printf.sprintf function to create a formatted string. The first argument to this function is the format string, which specifies how the remaining arguments should be formatted.

In the format string, %s is used to indicate that the next argument should be formatted as a string, %d is used to indicate that the next argument should be formatted as an integer, and %.1f is used to indicate that the next argument should be formatted as a floating-point number with one decimal place.

You can use a variety of format specifiers in the format string to control how the remaining arguments are formatted. For a complete list of format specifiers and examples, you can refer to the Printf module documentation.