1. First, we open word on the computer, and then click Insert.

2. Then we click on the document section in the toolbar to open the interface, and we click on the domain.

3. In the pop-up interface, we click to select AutoNum, then we click to select 1, 2, 3 ..., then we check the delimiter, and then click OK.

The result is as shown in the figure, so we inserted a field.