Provided your speed isn't 0, you can always move on your turn. Your speed dictates how many meters you can walk on your turn without using your action to move further. If you are playing on a grid, moving from one adjacent square to another uses 1 meter of your speed. There are other types of movement as well.
You move to an adjacent square without triggering reactions due to movement. To move in this way, you must spend all of your movement, regardless of maximum speed. Some features allow you to move further than 1 meter when you Step. If you have other movement types, you can Step while using them. Otherwise, you can only Step when you walk.
You crawl on the floor while remaining Prone. For every 1 meter you move in this way, you must spend 2 meters of your speed.
You scale a climbable surface, moving vertically or horizontally in a direction of your choice. This requires the use of at least one of your hands.
If your movement doesn't have the climb tag, climbing acts as difficult terrain, and you make all power rolls with a burden while climbing.
You swim through a body of water you are completely submerged in, moving vertically or horizontally in a direction of your choice.
If your movement doesn't have the swim tag, swimming acts as difficult terrain, and you make all power rolls with a burden while swimming.
If your movement has the fly tag, you can fly. When you fly, you can move freely horizontally. Flying upwards acts as difficult terrain, but when you fly downwards, you can move 1 meter horizontally for each meter you descend. When you fly, your stability is reduced to 0 for the duration of the flight.
While flying, you must move at least 1 meter on each of your turns to remain in the air; otherwise, you fall. Alternatively, you can use your maneuver to stay aloft and remain in your aerial position
You move stealthily to become or remain Hidden.