To put it simply, the fields in Word are generally some instructions, switches or references, which can be used to set the format of Word, compile directories, apply formula calculation and so on.

Update the domain, give two examples:

1. For example, if a field is used for calculation in a table, it is assumed that the numbers in two cells in the table are added. If you change the number in any cell, because fields are not usually updated automatically, you should right-click the field code and update the field.

2. If the table of contents is generated by using the function of automatically inserting the table of contents, it is possible that the page number of the originally generated table of contents is wrong, and the fields need to be updated at this time.