Moving a Robotic Arm in space can be done in different way described below. In each case it is helpful to be familiar with the XYZ coordinate system.

Command the arm to move to specific coordinates (X, Y, Z) in its workspace. When navigating in this way, the Robot Software will calculate the required movement of each joint for you (also called Inverse Kinematics). This in many cases the easier way to move the robot.

It is also possible to move each each axis separately (also called Forward Kinematics). For some use cases this makes sense, eg. to precisely calibrate a plane.

Movements can be relative to different points of view. They can be relative to the base of the robot, to the current perspective, to the tool or to the working surface. Being able to use different points in space as the origin of the coordinate system makes working much easier. Some examples:
Move in relation to Base: To move the robot in space using the teach pendant it is easiest to use the base of the robot as origin.
Move in relation to Plane: To draw something on a surface it is easiest to use a corner of the surface as a reference point
Move in relation to Tool : To precisely rotate a tool while staying at the same position in space you can use the Tool Center Point as origin.