Vectors are scalars with direction.
A vector indicates motion in a specific direction. (it has both magnitude and direction). This is different from scalars that represent only the magnitude. eg) distance is a scalar and displacement a vector.
Vectors can be used to describe motion due to the fact that motion is comprised of vectors.
Let's first recall the definition of a vector:
A vector is anything that has magnitude and direction.
Anything that has magnitude and direction. Let's take a moment to think of what magnitude and direction mean. Magnitude represents the strength of something or how strong it is.
For example, in science, a Newton (N) is a unit of strength. That is magnitude. Now, onto direction. Direction is, well the direction of something.
Combining the two, we get a vector. Something that represents both the direction of something as well as how strong it is. How are we going to relate the concept of the vector with motion? Let's see.
If you think about it, motion is essentially comprised of directions and how strong/ how fast you are moving in that direction. So therefore, motion is made up of vectors.
However, most of the time, motion is not just one vector. It's usually made up of multiple vectors all acting together to produce a combined mixture of directions and strength. For example, if you walk north from a starting point and then turn to the east and walk, it's the same as walking in the north-east direction from the starting point.
Hope this helped!