Please go to Admin dashboard -> Contact -> Contact Forms -> Edit or Create new Contact form and add code html to form:
<div class="row-inline row">
<div><label>Your name *</label>[text* your-name placeholder "John Doe"]</div>
<div><label>Your E-mail *</label>[email* your-email placeholder "[email protected]"]</div>
</div>
<div><label>Subject</label>[text* your-subject placeholder "This is an optional"]</div>
<div><label>Message *</label>[textarea textarea x5 placeholder "Hi! I’d like to ask about... "]</div>
<div>[submit "Submit"]</div>
If you need to help, please send Admin web account for me, I will check and help you.