How Do I Submit A String Into A Form?

Question

In JS I got a functional form, with a submit button, and the option to press the 'Enter' key to submit a string.

What I'm trying to do is create a button which enters a string into that form box, and submits it. I have managed to get the button to automatically enter the string, but the submission is giving me a bit of trouble. Should I try to have JS send an enter key trigger? Or is there a more efficient way to have the string auto submit itself?

function codeTest() { //This is what I'm testing
    document.getElementById(`inputBox`).value = "Let's see if this works." // The string is being entered in the box just fine
        //I just can't think of a way to submit the string into the input box.
}