You definitely want to use fixed when you want to move the header at any point, because position sticky is like having 2 properties at one, absolute and fixed. Using fixed will also give you more control over your header position. I hope this helps you on your project.
Thanks. But i find sticky easier to use. because for fixed i need to add maybe a margin and other codes for it not to overlap other content. while sticky i just need to add top:0;
But i am wonder if sticky should be completely avoided because some browsers dont support it and that its a bad practice to use sticky.