It all depends on the environment and specific circumstances but typically, not a great idea to touch them or pick up.
Many people find spiders to be intimidating and scary and they may have heightened anxiety because they associate spiders with death as mentioned in spooky stories like The Spider’s Lullabye which is really not true at all. Black widows are for example only found in North America, so there is no need to worry about black spiders associated with other continents. Spiders only pose a danger when they are disturbed or feel threatened. So the best thing would be not to expect any problems if you leave this spider where it is (on your window sill) but keep an eye on it if it moves upwards closer towards you.