It’s bunny’s natural instinct to resit being lifted. In the wild anything that would pick him up would be very bad! Some bunnies never get to the point where they’re completely comfortable being picked up and others eventually don’t mind it. Gizmo doesn’t necessarily like it, but we’ve gotten to the point now that he’s okay with it (once you can catch him that is). If you’re bunny likes to come to you and play with you, you can try sitting or lying down with him and see if he’ll hop into your lap or on your stomach. Then you can just put your arms around him and get up since he’ll be up against you. This is how we started with Gizmo. Also, you have to be really confident about picking him up, because if you hesitate for a moment he’ll be off and kicking and the more he manages to get away the more he’ll learn that kicking=freedom. I’ve also found that my bunny freaks out much less if I make sure I’m really supporting all his legs, so I scoop one arm under the front and one under the back legs rather than trying to get under his tummy. Also, try giving him a small treat and good petting after you pick him up so he learns that being picked up is good.
If he never gets used to it then you may just have a bunny that won’t allow picking up. In that case, if you have to pick him up for an emergency or vet visit or something you can toss a towel over him and scoop him up in the towel.