Add, change, or remove transitions between slides
A slide transition is the visual effect that occurs when you move from one slide to the next during a presentation. You can control the speed, add sound, and customize the look of transition effects.
Add slide transitions to bring your presentation to life
Select the slide you want to add a transition to.
Select the Transitions tab and choose a transition. Select a transition to see a preview.
Select Effect Options to choose the direction and nature of the transition.
Select Preview to see what the transition looks like.
To remove a transition, select Transitions > None.
Source: Microsoft