1.Open Microsoft PowerPoint and open the presentation you want to modify the master.
2.Select View in the top menu bar.
3.In the View menu, locate and select Master View. This will show you the master of the presentation and the corresponding layout.
4.In the Masters pane on the left, you'll see a list of masters and layouts for your presentation. Select the master or layout you want to modify.
5.In the Masters pane, you can make several modifications to the master or layout of your choice, such as changing colors, fonts, backgrounds, slide numbers, logos, and more. You can also add, remove, or rearrange content placeholders.
6.Click on the element on the master or layout that you want to modify and edit it accordingly. For example, you can change the title font or remove the copyright information at the bottom.
7.When you're done editing the selected master or layout, you can switch to a different master or layout as needed.
Note that changes made to the master will apply to all slides throughout the presentation. If you only want to change the design of a specific slide, you can select the Slide Master view from the View menu, and then make edits to the slide master.
Finally, remember to save your changes to the master so that you can keep them the next time you open the presentation.