It depends if you have ordered container grown products or bare-rooted ones. Bare-root ideally need to be planted, or at least heeled in to the ground, upon receipt but will be ok for several days if you keep the roots moist in the bag they’re wrapped in when they arrive. Container grown items can last much longer, just be sure not to let the roots dry out in their pots and keep them outside in the sunlight. After all, if they weren’t in your garden they’d still be in their pots on our tree lines or shrub beds.
There is a write up about this on our "Advice" page.