How to increase the size of oppo SMS if it is too small?

Here, take the OPPO R9S mobile phone as an example, and the specific methods are as follows:

First click the "Settings" icon on the mobile phone desktop, as shown in the figure.

2. Then select the "Display and Brightness" option in the setting interface of the mobile phone, as shown in the figure.

Third, open "Font Size" in the display and brightness interface, as shown in the figure.

4. Finally, slide the slider in the red box below to the right to enlarge the font of the short message, as shown in the figure.