sticky top bootstrap 4

1<div class="position-static">...</div>
2<div class="position-relative">...</div>
3<div class="position-absolute">...</div>
4<div class="position-fixed">...</div>
5<div class="position-sticky">...</div>

1<div class="fixed-top">...</div>

1<div class="sticky-top">...</div>

1<div class="sticky-sm-top">Stick to the top on viewports sized SM (small) or wider</div>
2<div class="sticky-md-top">Stick to the top on viewports sized MD (medium) or wider</div>
3<div class="sticky-lg-top">Stick to the top on viewports sized LG (large) or wider</div>
4<div class="sticky-xl-top">Stick to the top on viewports sized XL (extra-large) or wider</div>