• When two slides have two different sorts of content and formats, transitions like this are extremely effective. Using the appropriate transitions can help keep your presentation flowing and will also give it a professional look. Make it clear to your viewers that you're switching from one topic to the next.
• When the content and format of the slides are similar, it's best to employ transitions to show the audience that you've gone from one point to the next. If no transitions are employed and a slide is transferred to the next, the viewer may not realise there was a change at all. In this case, using transitions that are visually more noticeable, such as push, cover, and uncover, is recommended.

Read More: How you can copy slide master from one presentation to another in PowerPoint?