“Pick up” either means physically lifting something, or meeting a friend or maybe your kid to take them somewhere else. So for example: - He picked up grocery bag. - I need to pick up my son from school at 3pm. - I’ll pick you up from work at 12pm, and then we’ll go eat lunch?
“Pick out” means that you’re choosing something from a group of options, so it’s pretty synonymous with “choose”. So for example: - Help me pick out something to wear today! - I want to pick out the freshest watermelon from this group!