Если речь идёт о bootstrap 4, то используйте
margin-left: auto;
для параграфа в котором находится номер телефона. Либо используйте стандартные классы bootstrap, вроде
ml-auto
.
Вот пример вашего кода:
<nav class="navbar fixed-top nav-tabs nav-justified sticky-top" style="background-color: #6191A8">
<div class="container-fluid justify-content-start ">
<a class="navbar" href="#"><img src="data:image/png;base64,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" width="40" height="40"></a>
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<p class="ml-auto" ><img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAC8SURBVDhPrdC/CkFhGMfxN5tJSUmJ3ahEKUysBqtNbsUuGZXF6AZkodwBuQQpI0X+fR+dt95OOc6Db32Kt57fcMy/SqODrqcEVSM8HCuo6sEdOCGK0LXgDog6QpfEBfb4igpUTSHHd8gHVVeDDJyRk4dvGkNGNojJg7YEdpCRJdyROAqIvP4FVMQRMrJFHimsvbc95mjgbWUcIAc3yJH8dg0RWBYz+A+tjwO2JhbwDwygKoM2+pigil8z5gkCQz0CtfhC3AAAAABJRU5ErkJggg=="> +799323812</p>
</div>
</nav>