1, first open your system settings to find your preferences, click on the keyboard option as shown:

2, and then click to select the input source, and then click on the bottom left corner of the Add + sign.

3, select Simplified Chinese, select the five-stroke input method, and finally select Add.

This will allow you to use the five-stroke input method.

Expanded Information:

If the computer itself didn't have a five-stroke input method, you can use the mac's app store, search for Universal Five-Stroke Input Method, download and install it. This will allow you to use the five-stroke input method.