her iki inputa da w-50 float-left classlarını ekleyip dener misiniz?
<form action="#iletisim"class="contact"method="post"><div class="row"><div class="col-md-12"><div class="col-md-12 col-sm-10 input-group"><input class="form-control w-50 float-left"name="isim"placeholder="Ad Soyad"><input class="form-control w-50 float-left"name="eposta"placeholder="E-Posta"></div></form>
Bu şekilde ise halen alt alta gözüküyor
<form action="#iletisim"class="contact"method="post">
<div class="row">
<div class="col-md-6">
<div class="input-group">
<input class="form-control"name="isim"placeholder="Ad Soyad">
</div>
</div>
<div class="col-md-6">
<div class="input-group">
<input class="form-control"name="eposta"placeholder="E-Posta">
</div>
</div>
</div>
</form>
Alt alta gözükmekte halen