I read, people with motion sickness , we can give them "beta blockers" before the journey, can we ?

Not standard therapy: Since beta blockers can actually increase feelings of malaise as well as cause low blood pressure, unless anxiety is a major cause, this would not be first-line. Over-the-counter medicines like Meclizine (marketed in the U.S. As bonine) and use of ginger (as capsules or just crystallized ginger, which is also delicious!) work pretty well for most people.